To provide an IC module connecting method capable of connecting an IC module to a card main body by using a thermal adhesion layer for making it hard to conduct heat to a card base material on the card back face side and a composite IC card in which the appearance on the card back face of the IC module connecting part is made satisfactory.

In this method for connecting an IC module 1 of a composite IC card which is equipped with the IC module 1 having at least components for both contact type and non-contact type communication and a chip having the both type communicating functions in an IC chip to a card main body 8, at the time of mounting the IC module in a mounting hole 11 opened at the card surface side, and formed like a recession in a size large enough to house the IC module, the IC module is connected to the card main body by ultrasonic bonding.