diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index bbefea7c47fc3..58313c92ae311 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1867,7 +1867,9 @@ class Timedelta(_Timedelta):
     value : Timedelta, timedelta, np.timedelta64, str, or int
         Input value.
     unit : str, default 'ns'
-        Denote the unit of the input, if input is an integer.
+        If input is an integer, denote the unit of the input.
+        If input is a float, denote the unit of integer parts.
+        The decimal parts with resolution lower than 1 nanosecond are ignored.
 
         Possible values: