TRANSMISSION POSITION MEASUREMENT METHOD FOR LASER BEAM AND POSITION MEASUREMENT METHOD AND MEASUREMENT SYSTEM USING THE SAME MEASUREMENT METHOD

PROBLEM TO BE SOLVED: To provide the transmission position measurement method of a laser beam for measuring the transmission position of a laser beam in order to cope with the fluctuation of the optical path of the laser beam.SOLUTION: A laser beam is projected from a first spot 11 to a second spot 12 such that the laser beam is receivable at the second spot 12. The shielding/transmission of the laser beam is temporally switched at a third spot 13 intermediate between the first spot 11 and the second spot 12, and intermediate light reception point coordinates (X3, Y3) of the laser beam to be obtained when shielding the laser beam at the third spot 13 are acquired, and light reception spot coordinates (X2, Y2) of the laser beam to be obtained when transmitting the laser beam at the third spot 13 are acquired, and the transmission position of the laser beam is acquired from the intermediate light reception point coordinates and the light reception point coordinates.