An electromagnetic compressor capable of reciprocating a piston to suck in and compress a gas by the force of an electromagnet and the resilient force of a return spring and a manufacturing method therefor are provided. The compressor includes a cylinder assembly including a front cylinder portion, a rear cylinder portion, and a center hole capable of storing the piston for reciprocation and having a working chamber defined by means of the piston, and an electromagnet located between the front cylinder portion and the rear cylinder portion and capable of actuating the piston. The cylinder assembly and the electromagnet have an integral structure molded from a resin in a manner such that the internal passage is hermetically sealed with respect to the electromagnet and the electrically conductive member.