In a fuel injector, a valve unit consisting of a valve body and an injection plate is connected to a bottom end of a cylindrical housing. The valve unit is connected to the fuel injector after other components are assembled to the fuel injector. In the process of forming the valve unit, the valve body and the injection plate are coupled with each other, and then both are connected by welding. Then, the valve body having the injection plate welded thereto is inserted into a bottom end bore of the cylindrical housing, and then the valve body and the cylindrical housing are connected to each other by welding. A circular valve seat formed on the valve body is not deformed in the course of forming the valve unit and connecting the valve unit to the cylindrical housing.