PURPOSE: To freely lock and unlock an object with a locking/unlocking notched groove formed in an IC card at the time when an IC card reader cannot be operated by providing the IC card incorporating an IC chip with the locking/ unlocking notched groove.

CONSTITUTION: AD IC card 1 incorporates the IC chip, and a discrimination code is recorded in the IC chip, and the recorded discrimination code is read through an external terminal 2 by the IC card reader and is compared with a discrimination code recorded in the IC card reader; and when they coincide with each other, the object is locked or unlocked. A locking/unlocking notched groove 3 is formed in the IC card 1. This locking/unlocking notched groove 3 is formed in the side of the front end in the direction where the IC card 1 is inserted to the IC memory reader. Since the locking/unlocking notched groove 3 is provided in the IC card 1 in this manner, the object is locked or unlocked by the locking/unlocking notched groove 3 formed in the IC card 1 when the IC card reader cannot be operated because of a fault or the like.