The present invention provides a laser reference level setting device, by which it is possible to adjust irradiating positions of a laser beam in vertical and horizontal directions with a simple arrangement and without additional manpower and to measure a tilt angle. The device comprises a laser sighting device and a target, the target having a reflection surface for indicating a given position on the target, and the laser sighting device comprising a laser oscillating device having an emitting means rotatably supported and for emitting a laser beam and a light receiving means for receiving a reflection laser beam, a driving unit for rotating at least the laser beam emitting means of the laser oscillating device, and a control unit for controlling the driving unit to direct the laser beam to a given position on the target according to the light receiving condition of the reflected laser beam reflected from the reflection surface of the target.