To provide a pattern projection type three dimensional geometry measuring arrangement for easily and accurately measuring by generating a stripe pattern having a sign wave strength distribution with a simple and low cost constitution.

To an optical element which is constituted of at least one first optical part consisting of a material absorbing light of a specific wavelength and at least one second optical part of which the refractivity is identical to the material of the first optical part and transmitting light of a specific wavelength the incidence surface and emission surface of light are convex, concave or plane, the thickness of the first optical part in the optical axis direction varies in wave at a constant period in an arbitrary direction perpendicularly to the optical axis, light is cast and transmitted light is projected to the measuring object. The image data obtained by photographing the projection pattern of the specific wavelength formed on the measuring object is processed to obtain three dimensional geometry of the measuring object.