diff --git a/client/src/components/Calendar.tsx b/client/src/components/Calendar.tsx
index d6346fa..b748f86 100644
--- a/client/src/components/Calendar.tsx
+++ b/client/src/components/Calendar.tsx
@@ -219,7 +219,9 @@ export const Calendar = ({ project, myGuestId, mySlotsRef, editMode }: Props) =>
       );
     }
     if (info.event.id === MY_EVENT) {
-      return <div className="h-full w-full text-gray-600 overflow-hidden">{info.timeText}</div>;
+      return (
+        <div className="h-full w-full text-gray-600 overflow-hidden">{`${dayjs(info.event.start).format("HH:mm")} - ${dayjs(info.event.end).format("HH:mm")}`}</div>
+      );
     }
   }, []);
 
diff --git a/client/src/pages/Home.tsx b/client/src/pages/Home.tsx
index 9b44473..ad5a1b8 100644
--- a/client/src/pages/Home.tsx
+++ b/client/src/pages/Home.tsx
@@ -55,7 +55,7 @@ function ProjectDashboard({ involvedProjects }: { involvedProjects: InvolvedProj
           </NavLink>
         </div>
 
-        {involvedProjects.length > 0 ? (
+        {involvedProjects.length > 0 && (
           <div className="space-y-8">
             {/* All Projects */}
             <section>
@@ -70,8 +70,6 @@ function ProjectDashboard({ involvedProjects }: { involvedProjects: InvolvedProj
               </div>
             </section>
           </div>
-        ) : (
-          <EmptyState />
         )}
       </div>
     </div>
diff --git a/client/src/pages/Project.tsx b/client/src/pages/Project.tsx
index 43b552e..bdeb1a8 100644
--- a/client/src/pages/Project.tsx
+++ b/client/src/pages/Project.tsx
@@ -2,7 +2,13 @@ import { zodResolver } from "@hookform/resolvers/zod";
 import dayjs from "dayjs";
 import { useEffect, useState } from "react";
 import { useFieldArray, useForm } from "react-hook-form";
-import { HiClipboardCheck, HiClipboardCopy, HiOutlineCheckCircle, HiOutlineExclamationCircle } from "react-icons/hi";
+import {
+  HiClipboardCheck,
+  HiClipboardCopy,
+  HiInformationCircle,
+  HiOutlineCheckCircle,
+  HiOutlineExclamationCircle,
+} from "react-icons/hi";
 import { NavLink, useNavigate, useParams } from "react-router";
 import type { z } from "zod";
 import { editReqSchema, projectReqSchema, projectResSchema } from "../../../common/schema";
@@ -36,24 +42,30 @@ export default function ProjectPage() {
   } | null>(null);
 
   const [copied, setCopied] = useState(false);
+  const [isInfoExpanded, setIsInfoExpanded] = useState(!eventId); // 新規作成時は展開、編集時は折りたたみ
 
   const {
     register,
     handleSubmit,
     control,
     reset,
+    trigger,
     formState: { errors, isValid, isDirty },
   } = useForm<FormSchemaType>({
     resolver: zodResolver(formSchema),
     mode: "onChange",
     defaultValues: {
       name: "",
-      startDate: "",
-      endDate: "",
+      startDate: eventId ? "" : dayjs().format("YYYY-MM-DD"),
+      endDate: eventId ? "" : dayjs().add(6, "day").format("YYYY-MM-DD"),
       allowedRanges: [{ startTime: "00:00", endTime: "23:45" }],
     },
   });
 
+  const handleFieldFocus = () => {
+    trigger("name");
+  };
+
   const { fields, replace } = useFieldArray({
     control,
     name: "allowedRanges",
@@ -80,8 +92,8 @@ export default function ProjectPage() {
     setSubmitLoading(true);
 
     // 日付をISO形式に変換
-    const startDateTime = new Date(`${data.startDate}T00:00:00.000Z`).toISOString();
-    const endDateTime = new Date(`${data.endDate}T23:59:59.999Z`).toISOString();
+    const startDateTime = new Date(`${data.startDate}T00:00:00.000`).toISOString();
+    const endDateTime = new Date(`${data.endDate}T23:59:59.999`).toISOString();
 
     // range もISO形式に変換
     const rangeWithDateTime = data.allowedRanges?.map((range) => ({
@@ -184,13 +196,43 @@ export default function ProjectPage() {
                 <input
                   {...register("name")}
                   id="input-name"
-                  className="input w-full text-base"
+                  className={`input w-full text-base ${errors.name ? "input-error border-red-500" : ""}`}
                   placeholder="イベント名"
+                  onBlur={() => trigger("name")}
                 />
-                {errors.name && <p className="text-red-500">{errors.name.message}</p>}
+                {errors.name && <p className="text-red-500 text-sm mt-1">{errors.name.message}</p>}
               </div>
               {!project || (project && project.guests.length === 0) ? (
                 <>
+                  <div className="collapse collapse-arrow bg-blue-50 border border-blue-200 mb-4">
+                    <input
+                      type="checkbox"
+                      checked={isInfoExpanded}
+                      onChange={(e) => setIsInfoExpanded(e.target.checked)}
+                    />
+                    <div className="collapse-title text-sm font-medium text-primary flex items-center gap-2">
+                      <HiInformationCircle className="w-5 h-5" />
+                      開始日・終了日／時間帯について
+                    </div>
+                    <div className="collapse-content text-sm text-primary">
+                      <p>
+                        イツヒマでは、<strong>主催者側で候補日程を設定せずに</strong>日程調整します。
+                        <br />
+                        ここでは、参加者の日程を知りたい日付の範囲と時間帯の範囲を設定してください。
+                        <br />
+                        詳しくは、
+                        <a
+                          href="https://utcode.notion.site/1e4ca5f557bc80f2b697ca7b9342dc89?pvs=4"
+                          target="_blank"
+                          rel="noreferrer noopener"
+                          className="link"
+                        >
+                          使い方ページ
+                        </a>
+                        をご覧ください。
+                      </p>
+                    </div>
+                  </div>
                   <div className="flex gap-2">
                     <div className="flex-1">
                       <label htmlFor="input-start" className="text-sm text-gray-400">
@@ -200,16 +242,23 @@ export default function ProjectPage() {
                         type="date"
                         {...register("startDate")}
                         id="input-start"
-                        className="input w-full text-base"
+                        className={`input w-full text-base ${errors.startDate ? "input-error border-red-500" : ""}`}
+                        onFocus={handleFieldFocus}
                       />
-                      {errors.startDate && <p className="text-red-500">{errors.startDate.message}</p>}
+                      {errors.startDate && <p className="text-red-500 text-sm mt-1">{errors.startDate.message}</p>}
                     </div>
                     <div className="flex-1">
                       <label htmlFor="input-end" className="text-sm text-gray-400">
                         終了日
                       </label>
-                      <input type="date" {...register("endDate")} id="input-end" className="input w-full text-base" />
-                      {errors.endDate && <p className="text-red-500">{errors.endDate.message}</p>}
+                      <input
+                        type="date"
+                        {...register("endDate")}
+                        id="input-end"
+                        className={`input w-full text-base ${errors.endDate ? "input-error border-red-500" : ""}`}
+                        onFocus={handleFieldFocus}
+                      />
+                      {errors.endDate && <p className="text-red-500 text-sm mt-1">{errors.endDate.message}</p>}
                     </div>
                   </div>
                   <fieldset>
@@ -217,7 +266,7 @@ export default function ProjectPage() {
                     <div className="flex gap-2 items-center">
                       <div className="flex-1 flex gap-1">
                         <select
-                          className="input flex-1 text-base"
+                          className={`input flex-1 text-base ${errors.allowedRanges ? "input-error border-red-500" : ""}`}
                           value={fields[0].startTime.split(":")[0]}
                           onChange={(e) => {
                             replace([
@@ -227,6 +276,7 @@ export default function ProjectPage() {
                               },
                             ]);
                           }}
+                          onFocus={handleFieldFocus}
                         >
                           <option value="" disabled>
                             時
@@ -238,7 +288,7 @@ export default function ProjectPage() {
                           ))}
                         </select>
                         <select
-                          className="input flex-1 text-base"
+                          className={`input flex-1 text-base ${errors.allowedRanges ? "input-error border-red-500" : ""}`}
                           value={fields[0].startTime.split(":")[1]}
                           onChange={(e) => {
                             replace([
@@ -248,6 +298,7 @@ export default function ProjectPage() {
                               },
                             ]);
                           }}
+                          onFocus={handleFieldFocus}
                         >
                           <option value="" disabled>
                             分
@@ -262,7 +313,7 @@ export default function ProjectPage() {
                       <span>〜</span>
                       <div className="flex-1 flex gap-1">
                         <select
-                          className="input flex-1 text-base"
+                          className={`input flex-1 text-base ${errors.allowedRanges ? "input-error border-red-500" : ""}`}
                           value={fields[0].endTime.split(":")[0]}
                           onChange={(e) => {
                             replace([
@@ -272,6 +323,7 @@ export default function ProjectPage() {
                               },
                             ]);
                           }}
+                          onFocus={handleFieldFocus}
                         >
                           <option value="" disabled>
                             時
@@ -283,7 +335,7 @@ export default function ProjectPage() {
                           ))}
                         </select>
                         <select
-                          className="input flex-1 text-base"
+                          className={`input flex-1 text-base ${errors.allowedRanges ? "input-error border-red-500" : ""}`}
                           value={fields[0].endTime.split(":")[1]}
                           onChange={(e) => {
                             replace([
@@ -293,6 +345,7 @@ export default function ProjectPage() {
                               },
                             ]);
                           }}
+                          onFocus={handleFieldFocus}
                         >
                           <option value="" disabled>
                             分
@@ -306,7 +359,7 @@ export default function ProjectPage() {
                       </div>
                     </div>
                     {errors.allowedRanges && typeof errors.allowedRanges?.message === "string" && (
-                      <p className="text-red-500">{errors.allowedRanges.message}</p>
+                      <p className="text-red-500 text-sm mt-1">{errors.allowedRanges.message}</p>
                     )}
                   </fieldset>
                 </>
@@ -329,7 +382,7 @@ export default function ProjectPage() {
                             if (!response.ok) {
                               throw new Error("削除に失敗しました。");
                             }
-                            navigate("/");
+                            navigate("/home");
                             setToast({
                               message: "イベントを削除しました。",
                               variant: "success",
diff --git a/server/prisma/schema.prisma b/server/prisma/schema.prisma
index 9a3325e..d61d51f 100644
--- a/server/prisma/schema.prisma
+++ b/server/prisma/schema.prisma
@@ -18,7 +18,7 @@ model Project {
   id            String         @id @db.VarChar(21)
   name          String
   /// 注: 日付部分のみ利用。時間は考慮しない。
-  startDate     DateTime
+  startDate     DateTime 
   /// 注: 日付部分のみ利用。時間は考慮しない。
   endDate       DateTime
   /// 注: 現在は 1 つのみ設定可能
diff --git a/server/src/routes/projects.ts b/server/src/routes/projects.ts
index a9c0b0b..2d57c56 100644
--- a/server/src/routes/projects.ts
+++ b/server/src/routes/projects.ts
@@ -27,10 +27,13 @@ router.post("/", validateRequest({ body: projectReqSchema }), async (req, res) =
       data: {
         id: nanoid(),
         name: data.name,
-        startDate: data.startDate,
-        endDate: data.endDate,
+        startDate: new Date(data.startDate),
+        endDate: new Date(data.endDate),
         allowedRanges: {
-          create: data.allowedRanges,
+          create: data.allowedRanges.map((range) => ({
+            startTime: new Date(range.startTime),
+            endTime: new Date(range.endTime),
+          })),
         },
         hosts: {
           create: {
@@ -206,13 +209,13 @@ router.put(
           ? { name } // ゲストがいれば名前だけ
           : {
               name,
-              startDate,
-              endDate,
+              startDate: startDate ? new Date(startDate) : undefined,
+              endDate: endDate ? new Date(endDate) : undefined,
               allowedRanges: {
                 deleteMany: {}, // 既存削除
                 create: allowedRanges?.map((r) => ({
-                  startTime: r.startTime,
-                  endTime: r.endTime,
+                  startTime: new Date(r.startTime),
+                  endTime: new Date(r.endTime),
                 })),
               },
             },