In a laser scanner for optically scanning and measuring an environment, the scanner having a center which defines for a scan the stationary reference system of the scanner and the center of the scan, a light emitter which emits an emission light beam, a light receiver which receives a reception light beam reflected by an object in the environment of the scanner, a control and evaluation unit which determines, for a multitude of measuring points of the scan, at least the distance between the center of the scan and the object, the scanner, for registering a scene with several scans having different centers, being movable between the centers of the scans, and a scanner mouse for registering the path followed by the scanner between the different centers of the scans, the scanner mouse optically registering the movement of the laser scanner relative to a reference surface.