The invention provides a passenger detection device which can inhibit interferences caused by seat positions and sitting postures of the passengers and can prevent mis-detection. The passenger detection device (20) is arranged on a chair and has a plurality of detection members (21-28) to detect the passenger on the chair (10). The passenger detection device (20) has a first detection member set (31) and a second detection member set (32); the first detection member set (31) outputs a detection result showing that the passenger is detected to a chair elevating device (41A) which is used as a first device for driving the chair (10); the second detection member set (32) outputs the detection result showing that the passenger is detected to a safety belt prompting device (42A) which is used as a second device and is different from the first device (41); the first detection member set (31) is arranged on the surface (11a) of the chair (10) and is configured in a range larger than the rangeof the second detection member set (32).