PURPOSE: To promptly and surely perform hydraulic control so as to enable high pressure injection to be operated while an injection time to be reduced and form a control device in small size and light weight, by controlling working fluid of a servo piston in an injector device and an intake and an exhaust valve device to be circulated by a conical valve.

CONSTITUTION: An injector device X, lifting a valve 28 rapidly to an upward moving position if a solenoid coil 30 is electrified, allows working fluid in a valve chamber 45 to flow out by opening a conical valve chamber flow outlet 49. And a valve 27, moving from its downward motion to the upward moving position, opens a servo piston chamber flow inlet 42 by a difference between pressures of working fluid in a working fluid inlet 40 and in the valve chamber 45. While an intake valve device Y, moving upward a conical valve 66 if a solenoid coil 64 is electrified, allows working fluid to flow into a servo piston chamber 73 by opening a servo piston chamber flow inlet 74 while closing a flow outlet 75. And a piston 77 and a plunger 78 integrally move slowly downward till a bottom end surface of the servo piston 77 is adapted to a bottom end surface of the piston chamber 73, opening an intake valve 60, thereafter it is rapidly fully closed by the plunger 78.