To lock and unlock respective using facilities by one key, and to prevent illicit use of the key even if the key passes into another's hands.

Individual specific information on respective users, key collating device codes of respective key collating devices 6 and usable person information for indicating usable persons are stored in a key information issuing center 2, and when receiving a request from the user for wishing to issue a key 5, the individual specific information is supplied to a key issuing device 3 from the key information issuing center 2 to issue the key 5 writing in information for specifying an individual, the key collating device code and the usable person information are supplied to a key information registering device 4 from the key information issuing center 2, the key collating device code is registered in the key 5, and when inserting the key 5 into the key collating device 6, the individual specific information and the key collating device code are supplied to the key collating device 6, and the respective using facilities are locked and unlocked.