A holding device for fastening a laser instrument, in particular to a magnetic construction, a pipe, a wall rail and/or ceiling rail, and/or a wall, is disclosed. The holding device includes a basic frame, a receptacle device connected to the basic frame to accommodate the laser instrument and a fastening apparatus connected to the basic frame with a first fastening device. The first fastening device is configured to be rotatable around an axis of rotation relative to the basic frame from a first position into a second position.