To provide a locker locking system allowing delivery of an article to one from the other by using one locker by two users when a plurality of users use a locker facility provided with a plurality of lockers.

This locker locking system is formed by connecting a control device 30 to respective locking units 20 by combining a plurality of sets of portable units 10 for transmitting an identification signal by respectively arranging the locking units 20 composed of a control part 20B for controlling locking or unlocking of an electronic lock 20C on the basis of the identification signal received by a transmitting receiving part 20A in the locker. When an input person B approaches by having a portable unit 10B, the identification signal is received, and is checked up with a user list of the control device 30 from the control part 20B, and when confirming the fact of a member, the electronic lock 20C becomes a use restriction releasing state, and is locked by input by a confirming button 22, and when a receiver A approaches, the identification signal is confirmed by the control part so that the electronic lock 20C is unlocked in the use restriction relasing state.