Patent ID: 7950164

Claim:
A surface texture measurement apparatus for measuring texture of a measurement target surface of a measurement target object by detecting displacement of a contact part that occurs with the contact part being in contact with the measurement target surface, the surface texture measurement apparatus comprising: a table on which the measurement target object is placed; a stylus that has the contact part at a tip of the stylus, the contact part being brought into contact with the measurement target object; a holding member that holds the stylus while allowing the stylus to move, the holding member allowing the displacement of the contact part as the stylus moves in contact with the measurement target object; an elastic member that applies a force for pressing the contact part against the measurement target object due to elasticity in a state in which the contact part is in contact with the measurement target object; a detector holder that can move over, toward, and/or away from the table and supports the holding member rotatably so as to turn a displacement direction of the contact part; a rotary motor that is supported on the detector holder and drives the holding member, which is coupled to the rotary motor, to rotate; an elastic force adjustment member that is provided as a rotatable member that is concentric with the holding member; a joining section that loins the elastic force adjustment member with the holding member to maintain rotational positions relative to each other; and a restricting section that restricts rotation of the elastic force adjustment member at a predetermined rotational position, wherein a range of the rotational position of the holding member driven by the rotary motor includes a first rotation range and a second rotation range, which is different from the first rotation range, the first rotation range is a range in which the displacement direction of the contact part is adjusted in a state in which the joining section maintains the rotational position of the holding member relative to the rotational position of the elastic force adjustment member, the second rotation range is a range in which the rotational position of the holding member relative to the rotational position of the elastic force adjustment member changes because the restricting section restricts the rotation of the elastic force adjustment member, and the elastic force adjustment member increases or decreases an amount of elastic deformation of the elastic member according to the rotational position of the elastic force adjustment member relative to the rotational position of the holding member.