A control unit 1 for the lock of a safe having a front housing part 4 and a rear h housing part 3. A controller 6 is integrated in the control unit 1 that, when a correct combination is entered in the keypad 5, moves a module through a motor 11 in the number of turns corresponding with this combination. The module has a transmission board 8 integrated in the housing 2 of the control unit 1 and a bolt 9 for actuating the safe's lock.