PURPOSE: To disperse and reduce the stress to be generated in a buffer member when a buffer member contacts with a plunger or a regulating part by forming the contact surface of a buffer member, which is fitted to any one of a plunger and a regulating part of a main body, into the curved surface in an electromagnetic fuel injection device using the compressed natural gas fuel.

CONSTITUTION: A plunger 36 arranged in a tubular main body 12 is reciprocated along the axial direction by the electromagnetic work so as to open and close a valve 48, and injection of the fuel is thereby controlled. In a fuel injection device, in which a buffer member 52 is fitted to any one of a regulating part inside of the main body, which regulates the movement of the plunger at the time of opening the valve, and the surface of the plunger opposite to this regulating part, the contact surface of the buffer member is formed into the curved surface. Stress to be generated at the time of contact is thereby dispersed by this shape.