Measuring probe for measuring a three-dimensional shape of an object to be measured

A measuring probe including a stylus having a contact part to be in contact with an object to be measured, an axial motion mechanism having a moving member that allows the contact part to move in an axial direction, and a rotary motion mechanism having a rotating member that allows the contact part to move along a plane perpendicular to the axial direction by a rotary motion, the measuring probe comprising:

• an axial element housing member that supports the axial motion mechanism,
• a rotary element housing member that supports the rotary motion mechanism, and
• a displacement detector supported by and within the axial element housing member, for detecting displacement of the moving member, wherein
• in the measuring probe:
• the axial motion mechanism supports the rotary element housing member and the rotating member supports the stylus, or the rotary motion mechanism supports the axial element housing member and the moving member supports the stylus,
• the axial element housing member encloses an interference optical system including an interference light source, a reference mirror for reflecting light from the interference light source, and a target mirror disposed in the moving member for reflecting light from the interference light source, the interference optical system capable of causing interference of reflected light from the reference mirror and the target mirror to generate a plurality of interference fringes,
• the displacement detector can detect a phase shift in the plurality of interference fringes generated of the interference optical system, and
• when coming into contact with a surface of the object to be measured, the contact part is configured to freely change its position in three dimensions along a shape of the surface via the axial motion mechanism and the rotary motion mechanism.