A bone plate fixing device comprises a first bone contacting element with a rod-shaped connecting member and a second bone contacting element displaceable on the connecting member. A surgical instrument for applying the bone plate fixing device comprises a first tool element positionable on the second bone contacting element, and a second tool element removable from the first tool element, with a transportation device for stepwise transportation of the connecting member with the second tool element. The second tool element has toothing comprising a plurality of teeth forming several receptacles for engaging toothing of the connecting member. The toothing of the connecting member may be on a projection protruding from the connecting member. The toothing of the second tool element may have a pitch which corresponds to an integral multiple of a pitch of the toothing of the connecting member.