PURPOSE: To prevent the generation of high-order moire fringes, by bringing the amplitude transmissivity of a lattice to a sine wave form.

CONSTITUTION: A reference lattice 3 is constituted by using a material perfectly same to that of an observation lattice 6 and the amplitude transmissivity thereof is a sine wave form. This sine wave form lattice can be prepared by the interference of two plane waves. In the three-dimensional measuring apparatus of this constitution, the light of a white light source 1 is collimated by a collimating lens 2 and the image of the reference lattice 3 is formed on matter by a condensing lens 4. The lattice pattern deformed corresponding to the shape of the surface 9 of the matter 9 is passed through a condensing lens 5, the observation lattice 6 and an image forming lens 7 to recorde moire fringes between the observation lattice 6 and the surface 9 of the matter by a camera 8. Because the same sine wave form lattice is used as the reference lattice 3 and the observation lattice 6, no high-order moire fringes are recorded and desired moire fringes can be measured.