PURPOSE: To obtain an oil pressure press which is as compact as possible and has decreased the number of pipes and control apparatuses, by providing a base pump, etc. in an oil tank formed on the upper part of the oil pressure press body, or other means.

CONSTITUTION: A base pump 3 provided in an oil tank formed on the upper part of a machine body 1 being a body of an oil pressure press is controlled by pressure oil supplied to the back of a vane and is driven by a motor. An oil guage 18 is tightly provided on the oil tank, the pump 3 inlets oil into the oil tank, and also supplies discharged pressure oil to each oil pressure apparatus. Also, pilot pressure oil from a valve 15 is supplied to the pump 3 or its supply is stopped by prescribing pressure of the discharging side of the pump 3, and energizing and denergizing a solenoid valve 15, respectively. Also, a prefill valve 4 for operating a main cylinder device is provided so as to be freely press- contacted with the valve seat whose valve body 22 having a large diameter is provided on the machine body 1, and on the valve body 22, a small path communicating with each chamber for storing each part of the valve body 22 partitioned by the boundary of said valve seat is provided, and a check valve 26 is incorporated, in this small path.