The invention relates to a device (1) for monitoring the state of a protective device (2), wherein said protective device (2) comprises a first element (4) provided with an opening (5) and a second element (6) which is movable with respect to the first element (4) in such a way that the opening (5) is closable at least partially, the device (1) comprises a locking device provided with a locking element (18) by which the close state of the protective device (2) is removably lockable and is blocked in the currentless state of the locking device, said locking device is activable by the movement of the protective device (2) from the open to the close state thereof. Said invention is characterised in that the device (1) comprises a blocking device (40) provided with a blocking element (41) and said blocking element (41) prevents in the currentless state the activation of the locking device by blocking the blocking the movement of the locking element (18), thereby leading to the closed state of the protective device (2).