VEHICLE WEIGHT MEASUREMENT DEVICE

The present invention includes: a bottom plate (200) that contacts an arm of a suspension device; a piston (300) that is capable of pressing a diaphragm (230), which forms an oil chamber (201), the piston being on the upper-surface side of the bottom plate; and a pressure sensor (400) that detects the pressure of a measurement fluid R in the oil chamber, the pressure sensor being on the lower-surface side of the bottom plate. The bottom plate has a mechanism for stopping the rotation of the arm of the suspension device in the vicinity of the pressure sensor. A hanging rim part (504a) is formed on a flange part (302) of the piston. A gap is formed between the flange part and the bottom plate. The bottom plate is provided with a step part (207) aligned with the hanging rim part. A stopper ring (320) provided so as to cover the step part from the hanging rim part is provided. A projecting part (300a) of the piston that fits with a notch part (322) of the stopper ring, and a projection part (205b) that fits with the notch part so as to be capable of moving in the longitudinal direction and projects from the upper-surface side, are also provided.