The present invention relates to a medical instrument for applying a bone plate fixing device which comprises a first bone contact element with a rod-shaped connecting member protruding therefrom and defining a longitudinal direction and a second bone contact element which is movable on the connecting member towards the first bone contact element, characterized by a feed apparatus comprising a feed element for application to the second bone contact element, a guide element with a proximal and a distal end for guiding movement of the feed element and a feed mechanism for moving the feed element in the distal direction relative to the guide element.