PURPOSE: To improve an antenna characteristic without changing the thickness of a card by setting the mounting face of a circuit pattern and a pattern for connection on different planes, in a thin non-contact IC card having a plane antenna.

CONSTITUTION: A ground conductor is formed on the back face of a card dielectric substrate 100, and the circuit pattern is formed on the surface of the card dielectric substrate 100. The pattern for connection which transfers an electric signal between an antenna conductor and the circuit pattern is formed on one face of a first dielectric 700, and the other face of the first dielectric 700 is mounted at the prescribed position of the surface of the substrate 100. Also, the antenna conductor is formed on one face of a second dielectric 200, and the other face of the second dielectric 200 is mounted so as to be opposed to the face of the dielectric 700 on which the pattern for connection is formed. Then, the pattern for connection is connected with the circuit pattern like direct current, and the electric signal is radiated from the circuit pattern through the pattern for connection and the antenna conductor to air as an electromagnetic wave. Thus, the antenna characteristic can be improved without changing the thickness of the thin card.