Abstract: Provided are a variable-capacity compressor control valve with a reduced number of component machining steps, a reduced machining cost, a reduced number of components, and a reduced number of assembly steps as well as reduced sizes of components, and with a simple configuration that can adjust the bellows attachment length and can secure airtightness, and a method for assembling such a control valve. A closure member, which is adapted to close an upper-portion opening of a cylindrical stator on the side opposite to an attractor, is press-fitted into the upper-portion opening and welded therein.