PURPOSE: To improve mechanical strength and to reduce stress generating at an IC tip by utilizing carbon fiber reinforced aluminum alloy as a card subtrate.

CONSTITUTION: Carbon fiber reinforced aluminum alloy is used as a card substrate 15. Accordingly, the rigidity of the entire IC card can be improved and deformation due to external force can be drastically reduced. Also the stress generating at the IC tip can be reduce and the deformation due to the external force can remain extremely small, so a trouble of an IC module 4 deviated from the card substrate can be avoided. An IC circuit board served as the card substrate in a conventional IC card is also formed by utilizing the carbon fiber reinforced aluminum alloy. An IC module is constructed by such IC circuit board, an IC tip and precoat resin. That is, the card subtrate consists of the IC module. The same effect can be obtained by utilizing either method, and the trouble of the IC module deviated from the substrate can be resolved.