The invention concerns a locking/unlocking device for a swivel latch of a door opener with a locking lever, that locks or unlocks the swivel latch, and a safety lock that holds the locking lever in a locking position and can be swiveled with the help of an electromagnet in a position unlocking the locking lever, wherein the safety lever is positioned in its center of gravity. Thus only one safety lever is required for the impact safety of the door opener, the susceptibility to shocks and vibrations can be reduced and a space-saving arrangement can be achieved. In a preferred form of execution, the safety lever has two arms wherein the electromagnet is in active connection with one lever arm and a compression spring is in active connection with the other lever arm. The assembly of the device is position-independent.