The present invention relates to a locking device 2 for objects of use, which are to be used for a particular period of time by a user, whereby the locking device 2 opens after the input of an opening code 4. The locking device is distinguished in that after input of an end code 6 the locking device issues a confirmation code (8) and changes the opening code in a particular manner (4.fwdarw.4'). Further, the invention relates to a method for the controlled, time-restricted, use of objects of use, which employs the locking device 2. In this method, an opening code 4 is issued by an access control unit 1, the opening code 4 is input into the locking device 2 for opening the same, an end code 6 is input for ending the use and then a confirmation code 8 is issued, the opening code being altered (4.fwdarw.4') by means of the locking device 2.