A controller including a case provided with at least one opened surface, a cover opening and closing the at least one opened surface, and a circuit board provided within the case and provided with a heating unit. The cover includes a cover body and a heat radiation unit in which at least a portion of the inner surface of the cover body is concave toward the circuit board so as to be closely adhered to the heating unit for the purpose of heat radiation. Thereby, heat within the controller may be effectively radiated and the lifespan of electrical devices may be extended.