PURPOSE: To measure a distance over a wide range by mounting a rotary beam projection means rotating while projecting two laser beams holding a definite angle, a beam detection part detecting two laser beams and an operation part receiving a beam detection signal to calculate a distance.

CONSTITUTION: One laser beam generated by a laser generator is emitted in a vertical upward direction from the lower part of a turntable 10 and passes through the hole 10a formed to the center of the turntable 10 to be incident to a prism 11. Next, the laser beam is changed by 90° in its advance direction by the prism to advance in parallel to the upper surface of the turntable 10 and incident to the vicinity of one end parts of a plurality of prisms 12 mounted to the peripheral part of the turntable 10. Next, the laser beam is divided into two laser beams A, B and a laser stand 1 rotates while emits two laser beams A, B and the beams A, B rotated by 360° within a horizontal plane while hold a definite angle θ0. A beam detection sensor 14 having width W1 is arranged to the beam detection part 2 of a target 20 to successively detect the beams A, B and a beam detection signal generation part generates a beam detection signal. This beam detection signal is transmitted to a time operation part to calculate beam detection time difference and this clocking data is transmitted to a distance operation part.