A door blocking device (1) including a retaining member (10) movable, along a given path, between a work position and a rest position, in which it respectively cooperates with and does not cooperate with a coupling member (8) of the door (2) when the door is in a closed position; and controlled-actuation means (11) for controlled actuation of the retaining member, and which include elastic means (13) for pushing the retaining member into the rest position; means (14) for moving the retaining member into the work position in opposition to the elastic means; a rotary member (15) having at least one radially projecting peripheral lobe (16) ; and an electrically controlled actuator (18) for moving the rotary member selectively between a first angular position, in which the at least one lobe does not interfere with the given path (T) , thus allowing the retaining member to move between the work position and the rest position, and a second angular position, in which the lobe interferes with the given path to lock the retaining member (10) in the work position in opposition to the elastic means.