APPARATUS FOR MEASURING SHAPE OF OBJECT

PURPOSE:To measure a complicated shape and to miniaturize the title apparatus, by providing a reflecting mirror to the beam path of laser beam for irradiating an object to be measured in a freely advancing and retracting state. CONSTITUTION:Optical systems A, B are received in a head 1 and a reflecting mirror 17 is provided to the beam path of the irradiation beam (a) from a projection lens 4 in a freely advancing and retracting state. At first, when the shape of the hole part 10a of an object 10 to be measured is measured, the reflecting mirror 17 is preliminarily retracted to the position shown by a broken line. At this time, the irradiation beam (a) is reflected by a flat mirror 7 and transmitted through a window art 8 to be incident to the surface of the hole part 10a and the beam spot thereof is condensed by a receiving lens 5 to be incident to a photodetector 6. Next, when the shape of a flat part 10b is measured, the reflecting mirror 17 is preliminarily allowed to advance to the beam path of the irradiation beam (a) and the irradiation beam (a) is reflected by reflecting mirrors 17, 27 to be incident to the surface of the flat part 10b. The photodetector 6 outputs electric signals I1, I2 to a processing circuit 2 corresponding to the image forming positions of the beam spots and the circuit 2 changes over the signals from the element 6 of the optical systems A, B to calculate image forming positions to measure the shapes of both of the hole part 10a and the flat part 10b.