To measure a concave large aperture surface to be inspected wholly in a state as it is in which self-weight deformation is added within a range where a measuring device can be arranged.

The shape measuring device is composed of an interferometer main body 1, a condenser lens 2, a reflector 3 having a reflecting face, a turning mechanism 6 giving the reflector 3 turning of a predetermined angle, a hold and adjust mechanism 5 holding and adjusting an object to be inspected 4, an image pickup means 10 detecting the interference fringe of the interferometer main body 1 as image information, and a processing means image-processing the image information.