A priority flow rate control valve (30) distributes pressurized working oil discharged from a hydraulic pump (10) driven by an electric motor (11) to a power steering device (20) first, and distributes the residual pressurized working oil to a cargo handling device (19). The rotation speed of the electric motor (11) and the distribution ratio of the pressurized working oil of the priority flow rate control valve (30) vary depending on the operation states of these devices (19, 20). By decreasing the rotation speed of the electric motor (11) at a rate smaller than a normal decrease rate when the cargo handling device (2) stops operation in a state where the power steering device (20) and the cargo handling device (19) are in operation, a kickback in a steering wheel (7) due to a response delay of the priority flow rate control valve (30) can be prevented.