By accurately determining timing for suppressing overrun in a hydraulic motor or the like, work efficiency is prevented from falling. A. pressure difference ΔP between pressure Pa on a discharge port side of a hydraulic pump and pressure Pb on suction port side of the hydraulic pump is calculated on the basis of the detected travel direction of the vehicle and the pressure Pa relative to Pb detected at the respective port sides of the hydraulic pump. At least one of an engine and the hydraulic pump is controlled, according to the calculated pressure difference, such that overrun of at least one of the engine, the hydraulic pump, and a hydraulic motor is suppressed.