Prison Act Article 54

Prisons shall provide inmates with suitable space, facilities, and equipment for exercising.With the exception of public holidays, rest days, or special circumstances, prisons shall allow inmates to exercise one hour each day.To maintain the health of inmates, the exercise space should be set up outdoors in principle; where necessary, inmates may exercise or participate in activities for relaxation at suitable places indoors.
中文原文 監獄行刑法第54條
監獄應提供受刑人適當之運動場地、器材及設備。
監獄除國定例假日、休息日或有特殊事由外,應給予受刑人每日運動一小時。
為維持受刑人健康,運動處所以安排於戶外為原則;必要時,得使其於室內適當處所從事運動或其他舒展身心之活動。

English translation for reference only; the Chinese text prevails. Not legal advice.