The object of the invention is to provide a noncontact IC card reader/writer integrated with an antenna that does not require the limitation of an installation location and the adjustment of a resonance frequency of the antenna, is convenient in installation, is provided with a stable characteristic, is small-sized and low-priced. To achieve the object, the invention is provided with a loop antenna that supplies electric power and send data to a noncontact IC card by electromagnetic induction and acquires receive data from the noncontact IC card by load fluctuation, a magnetic body arranged closely at the back of the loop antenna, a first metallic plate arranged on the back side of the magnetic body and a second metallic plate arranged on the back side of the first metallic plate and larger than the first metallic plate in size.