Optical displacement meter

An optical displacement meter of a light sectioning method that measures a cross-sectional profile of a workpiece having a height in a Z direction based on a principle of triangulation, the optical displacement meter comprising:

• a light projecting/receiving module including a light projecting unit that emits slit light extending in an X direction, a light receiving lens that collects reflected light of the slit light reflected by the workpiece, and an imaging unit that receives light collected by the light receiving lens;
• a motor that integrally rotates the light projecting/receiving module;
• and
• a control unit that controls the motor to scan the slit light during a first measurement operation in a direction orthogonal to the X direction,
• wherein the control unit controls, during the first measurement operation, the motor to rotate the light projecting/receiving module in an angle range which does not include a predetermined angle at which the light receiving lens collects specularly reflected light reflected from a specular reflection surface when the light projecting unit irradiates the workpiece having the specular reflection surface, parallel to an X-Y plane extending in the X direction and a Y direction, and
• the control unit controls, during the first measurement operation, the motor not to rotate the light projecting/receiving module in another angle range which includes the predetermined angle.