To realize an easy maintenance of the load sensor.A passenger's weight measurement device includes a left and right pair of fixed lower rails which are fixed on the vehicle floor, a left and right pair of movable upper rails which are disposed to move in a front-and-rear direction on the fixed lower rail, load sensors which are fixed to an upper surface of the right movable upper rail, load sensors which are disposed on the movable upper rail to be movable in a left-and-right direction with respect to the right movable upper rail, a sub frame which is mounted on the load sensors, side frames which are welded to the sub frame, and a pan frame which is detachably disposed to the side frames to cover the front of the side frames. A gouged section is formed on the side frame.