PURPOSE: To disperse the load applied to a moving valve cam shaft and its bearing by setting the coupling position of a pump drive shaft driving an oil hydraulic pump engaged to the moving valve cam shaft properly with a plunger.

CONSTITUTION: The position of a coupling section 78b between an eccentric cam 72 reciprocally driving an oil hydraulic pump P and a plunger 79 is arranged in a different circumferential phase relative to the coupling position between a moving valve cam shaft 60 and suction and exhaust locker arms 64,65. Accordingly, the load applied to the moving cam shaft 60 and a bearing 66 can be dispersed. When the moving cam shaft and a pump shaft 71 are rotated by the action of an engine E of the oil hydraulic pump P, the eccentric cam 72 together with a spring 82 moves the plunger 79 reciprocally, thereby the oil in a pump chamber 76 is compressed and the pressure oil is fed into an accumulator Ac through a discharge valve 88.