Abstract: A hammer drill for manually guided operation includes an electric drive motor, a tool spindle and a pneumatic hammer function. The hammer drill includes a pressure piston, a striker, and a beat piece for striking axially against a tool that is held by the tool spindle. When the striker reaches a forward limit position, an end section thereof protrudes into a retaining ring that is aligned coaxially with the spindle axis. Manufacturing quality can be improved by bracing the retaining ring against an annular collar in the tool spindle on the one side and axially against a locking ring set in an annular groove conformed in the tool spindle via a retaining disc on the other side. The retaining ring, the retaining disc and the non-return disc are each mirror-symmetrical.