A device for aligning two machine shafts which are coupled to one another has: at least one laser light source for emitting laser light; at least one reflector for reflecting the laser light; at least one receiving device for receiving the laser light; a first arithmetic computing device for determining parallel and angular offset of the machine shafts; and an evaluation and arithmetic computing device for determining the distance of the machine mounting elements relative to the plane of symmetry which lies between the machine shafts. The plane of symmetry intersects the axes of the machine shafts essentially perpendicular to longitudinal axes of the shafts, i.e. with an angular error of less than 6°.