An occupant load sensor (10) is fixed to a bracket (48) via a sleeve (60a) of a collar (60) arranged in an outer periphery of a thread (32) of a bolt portion (30), and a bush (62) interposed between the sleeve (60a) and a through hole (48a) of the bracket (48). Accordingly, a slight movement is allowed between the bolt portion (30) and the bracket (48) on the basis of gaps formed between the thread (32) and the sleeve (60a) and between the sleeve (60a) and the bush (62), and it is possible to cancel a force applied from the other directions than a vertical direction. Therefore, a load from the seat side is applied in the vertical direction and it is possible to accurately detect.