Method of manufacturing fuel injector for internal combustion engine

A method of manufacturing a fuel injector which comprises a cylindrical housing in which a valve needle is slidably disposed, a valve body connected to a bottom end of the cylindrical housing, and an injection plate connected to a bottom end of the valve body, wherein the valve body includes a circular valve seat on which the valve needle is seated, and the injection plate includes a bottom plate having injection holes which are opened and closed according to reciprocal operation of the valve needle and a circular sidewall, the method comprising steps of:

• inserting the bottom end of the valve body into an inside space of the circular sidewall of the injection plate, an inner diameter of the circular sidewall being made not to deform the valve body;
• connecting the bottom plate of the injection plate to the bottom end of the valve body by welding;
• inserting an upper end of the valve body into the bottom end of the cylindrical housing;
• and
• connecting the valve body to the cylindrical housing by welding an outer periphery of the bottom end of the cylindrical housing.