Three-dimensional shape measuring device, reference surface position adjustment method therefor, and measurement mode switching method therefor

A three-dimensional shape measuring device comprising:

• a light source unit configured to emit measurement light that is white light;
• an interfering unit configured to:
• separate as reference light, part of the measurement light emitted from the light source unit to emit the measurement light to a surface to be measured and emit the reference light to a reference surface;
• and generate interference light of the measurement light returning from the surface to be measured and the reference light returning from the reference surface;
• a holder configured to house the interfering unit and the reference surface, wherein the holder is formed of a material that reversibly thermally deforms in response to temperature change and causes a reference light path length which is an optical path length of the reference light between the interfering unit and the reference surface, to change in response to the temperature change;
• and
• a temperature adjusting unit configured to adjust, in a case where an optical path length of the measurement light between the interfering unit and the surface to be measured is set as a measurement light path length, a temperature of the holder to a target temperature at which the reference light path length becomes equal to the measurement light path length.