| 摘要 |
PROBLEM TO BE SOLVED: To enable high-precision measurement with small aberration variation even when the focus is adjusted when the shape of an inspected surface and the wave front aberration of an optical system are measured. SOLUTION: The light emitted from a light source 1 is split into measuring light and reference light, the measurement light is made incident on the inspected surface 6, and interference fringes formed by the interference between the measuring light reflected by the inspected surface 6 and the reference light are detected by a detector 9. In this case, movable mirrors 7b and 7c which can vary the length of the interference optical path after the measurement light and reference light interfere with each other are provided in the interference optical path.
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