The present invention intends to prevent the communication distance from becoming shorter with a reduction in size of a coil antenna to the chip size and with a consequent decrease of an induced voltage. According to the present invention there is provided a semiconductor chip having a coil antenna and a circuit surface and adapted to transmit and receive signals by radio to and from an external device. The semiconductor chip has a configuration for increasing an electromagnetic coupling coefficient between the coil antenna and the external device. According to a concrete example thereof, a magnetic material is disposed, the coil antenna is formed by a stacked structure comprising plural conductor layers and insulating layers superimposed one on another, or the coil antenna is disposed outside an external form of a circuit of the semiconductor chip.