To provide a monitoring device wherein a safety switch is mechani cally locked with non-contact release and driving is enabled only when a mov able element is actually locked.

The safety switch provided with a housing 2 connected to an evaluating device and disposed adjacent to the movable element 9 is included, the safety switch is provided with a reading head 5 to read data stored in a codified release mechanism 12 provided on the movable element at a locking position in the movable element, the movable element is provided with a driver 6 which locks the movable element at a locking position at an end position in the housing and comes into contact with the mechanism, the housing has a space 3 to receive the driver 6 and accommodates the reading head at a position adjacent to the release mechanism at an end of the driver 6 in the housing, the driver 6 may be moved against the movable element by communicating with a handle 8 provided on the movable element.