Fuel injection device

A fuel injection device configured to inject fuel by a solenoid actuator, the fuel injection device comprising:

• a casing in which a fuel injection hole is formed in a tip portion and a fuel passage that allows the fuel injection hole and a fuel inlet port to communicate with each other is formed inside the casing;
• a spool disposed inside the casing to be movable along an axial direction of the casing by operation of the solenoid actuator, the spool including
• a needle valve disposed on one end side of the spool to be capable of opening and closing the fuel injection hole, and
• a drive piston having a piston surface disposed on the other end side of the spool to face a pressure control chamber that communicates with the fuel passage;
• and
• a depressurization flow passage formation member having an outlet port that is opened and closed by the operation of the solenoid actuator and an opening formed on a facing surface facing the piston surface, the depressurization flow passage formation member having a depressurization flow passage that communicates with the pressure control chamber and that is formed inside the depressurization flow passage formation member,
• wherein the piston surface has a protruding part that protrudes toward an opening side, and the depressurization flow passage formation member has an inclined surface that is inclined from the opening to be tapered in a direction away from the piston surface, and
• the protruding part has a linear contact portion that comes into linear contact with the inclined surface and is capable of closing the opening when the piston surface is moved to the other end side.