The hours during which someone works at a company or workplace; the span or amount of working hours.
今月は出張が多くて勤務時間が不規則だった。
This month I had many business trips, so my working hours were irregular.
医師の勤務時間は病院によって異なることが多い。
Doctors' working hours often vary depending on the hospital.
勤務時間中は私用の電話を控えてください。
Please refrain from personal phone calls during working hours.