PURPOSE: To provide an injector which improves the suppression of noise and exhaust characteristics by providing a part in which lift speed becomes high and a part in which lift speed becomes low when a needle valve is lifted.

CONSTITUTION: An oil pressure control section 8 is formed with a cylinder 7a of a command piston 7 and a control chamber 8a, and the control chamber 8a is formed with a slide piece 8c provided in a second oil passage 14a, a return spring 8e, and a first oil passage 14b. A three-way valve 9 which changes over a fuel oil supply passage (oil passage 9d) connected to an operating fluid come-in and come-out passage and a fuel reflux passage 9e sequentially is attached, and a projection 15 which comes in and out in the first oil passage 14b is provided on a pressure receive face 7c to control lift speed of a needle valve of an injector.