A paper sheet processing apparatus capable of preventing paper sheet clogging in a traveling route in which a paper sheet is conveyed is provided. The paper sheet processing apparatus comprises an open/close member 2B which is opened or closed with respect to a frame 2A and a traveling route through which the paper sheet (a bill, a card, a coupon ticket, and the like are collectively referred to as “paper sheet”) is conveyed is formed between the open/close member 2B and the frame 2A when the open/close member 2B is closed with respect to the frame 2A. The open/close member 2B is provided with a sensor 31 for detecting that the open/close member 2B is opened from the frame 2A.