A fuel injector includes a valve body moved together with a movable core and opening an injection port, and an elastic-force applying portion being elastically deformable according to a movement of the valve body to apply an elastic force to the valve body in a valve-closing direction. An elastic coefficient of the elastic-force applying portion is set to meet a condition that Ffc−Ffo≦L×K. In this case, a fuel-pressure valve-closing force of when the valve body is closed is referred to as Ffc, and the fuel-pressure valve-closing force of when the valve body is completely opened is referred to as Ffo. A movement distance of the valve body from a time point that the valve body is closed to a time point that the valve body is completely opened is referred to as L. The elastic coefficient is referred to as K.