A slide of a press machine is driven by composite thrust of thrust of an electric (servo) motor SM (via a screw/nut mechanism from the electric motor) and thrust of hydraulic cylinders SYL1, SYL2 to which pressure oil is supplied from a constant, high pressure source. A slide control device controls the electric motor SM and the hydraulic cylinders SYL1, SYL2, based on a slide position signal and a motor angular velocity signal, and at the same time, makes the hydraulic cylinder SYL1 work as a pump during a period when slide load is small, charging pressure oil to the constant, high pressure source by using the thrust transferred from the electric motor to the hydraulic cylinder SYL1 through the screw/nut mechanism and the slide.