An IC device (10) held on an IC carrier (24) is a double-sided electrode type BGA IC device (10) provided with bump electrodes (14) on a first surface of a package. The IC device has, on a second surface opposite the first surface, (a) a central protrusion (30), (b) a peripheral portion (32) lower than the protrusion by one step, and (c) upper electrodes (18) formed on the peripheral portion of the IC device. The IC carrier is provided with a frame (36), a cover (40), and a holding means (42). The frame forms a device reception space (38) for receiving the IC device. The cover can cover the upper electrodes while in contact with the periphery of the IC device held on the IC carrier. The holding means can hold the IC device on the IC carrier with the cover covering the upper electrodes of the IC device. The IC device can be set in an IC socket while being mounted on the IC carrier.