An IC body is loaded on a case made of a thermoplastic resin material and sealed to the case with a sealing portion made of thermoplastic resin material, whereby an IC card is manufactured. The IC body includes a wiring substrate formed with an external connection terminal at a back surface thereof, a semiconductor chip loaded over a surface of the wiring substrate and electrically connected to the external connection terminal via an interconnect, and a sealing portion made of thermoplastic resin material so as to cover the semiconductor chip and a bonding wire. The sealing portion is formed so that the external connection terminal is exposed. Thus, making it possible to increase the strength of IC cards and, at the same time, to reduce the manufacturing cost and improve the reliability.