To suppress the influences of a pressure fluctuation with the opening/closing operation of a needle, on a fuel flow flowing into a nozzle hole.

The fuel injection device comprises a valve body 21 in which a vertical hole (a first inner periphery) 21a and a tapered portion 24 at the downstream-side end of the vertical hole are formed and which has a nozzle hole 22 communicated with the vertical hole and passing through the inside to the outside, an outer needle 6 axially movable inside the vertical hole and to be seated on or separated from the tapered portion, and a seat part 25a where the outer needle is seated on or separated form the tapered portion, wherein operating force operates on the outer needle in a valve opening direction with high pressure fuel supplied from a common rail 9 which stores the pressure of the high pressure fuel. Between the peripheral faces of the vertical hole and the outer needle 6 where the size of an opening between the peripheral faces is not changed with the movement of the needle in the valve opening direction, a throttle part 33 is provided for restricting fuel when guided to the seat part. The throttle part specifies the maximum amount of the fuel to flow into the nozzle hole.