PURPOSE: To reduce a pressure impact having influence on dynamics of a valve needle of a fuel injection valve by reducing a cross sectional area of a throttle opening with a cutout moving together with a thrust pin during the opening stroke of the valve needle.

CONSTITUTION: In this injector, a thrust pin 48 is formed with a cutout 50 having a trapezoidal shape in section along an axis 51 of a valve needle 31. A connection opening becomes narrow in a funnel state from a chamber filled with fuel to form a throttle lip 53 in a transition part to a buffer chamber 39. Thereby, first, a step part follows the throttle lip 53, next, a stopper 40 follows the step part. When the valve needle 31 descends, a cross sectional area of a throttle opening 54 is maximum. The cross sectional area of the throttle opening 54 is gradually reduced by a restricting wall of a slant side face of the trapezoidal cutout 50 as the valve needle 31 moves upward.