diff --git a/src/lib/utils/contest.ts b/src/lib/utils/contest.ts
index 3e79f2fd4..244117fcd 100644
--- a/src/lib/utils/contest.ts
+++ b/src/lib/utils/contest.ts
@@ -156,6 +156,7 @@ const ATCODER_OTHERS: ContestPrefix = {
   colopl: 'COLOCON',
   gigacode: 'GigaCode',
   cpsco2019: 'CPSCO 2019',
+  DEGwer2023: 'DEGwer さんの D 論応援コンテスト',
 } as const;
 const atCoderOthersPrefixes = getContestPrefixes(ATCODER_OTHERS);
 
diff --git a/src/test/lib/utils/test_cases/contest_type.ts b/src/test/lib/utils/test_cases/contest_type.ts
index a16068f93..db1457862 100644
--- a/src/test/lib/utils/test_cases/contest_type.ts
+++ b/src/test/lib/utils/test_cases/contest_type.ts
@@ -288,16 +288,16 @@ export const atCoderOthers = [
     contestId: 'gigacode-2019',
     expected: ContestType.OTHERS,
   }),
-  createTestCaseForContestType('CPSCO2019 Session1')({
-    contestId: 'cpsco2019-s1',
-    expected: ContestType.OTHERS,
-  }),
   ...[1, 2, 3, 4].map((session) =>
     createTestCaseForContestType(`CPSCO2019 Session${session}`)({
       contestId: `cpsco2019-s${session}`,
       expected: ContestType.OTHERS,
     }),
   ),
+  createTestCaseForContestType('DEGwer さんの D 論応援コンテスト')({
+    contestId: 'DEGwer2023',
+    expected: ContestType.OTHERS,
+  }),
 ];
 
 // See: