An ECU is configured to determine the life of a pressure storage tank. The pressure storage tank has a gas chamber filled with gas, an oil chamber connected to a common passageway, and a piston dividing the gas chamber and the oil chamber. The pressure storage tank is configured to store hydraulic oil in the oil chamber and to release the hydraulic oil from the oil chamber. The ECU calculates a movement amount of the piston based on the volume change of the gas chamber. The ECU determines that the life of the pressure storage tank has ended when an integrated value of the calculated movement amount exceeds a threshold value.