To restrict a movement in an axial direction of a rotary shaft by an inexpensive constitution.

A permanent magnet 7 is set to a cup 8 fixed to the rotary shaft 9, and a Hall element 5 is set for detecting the rotation of the permanent magnet 7 in a noncontact manner, whereby a displacement of an object to be detected is detected by the Hall element 5 in a noncontact displacement sensor 10. The noncontact displacement sensor 10 is provided with a housing 11 for supporting the rotary shaft 9 rotatably and restricting the movement in one axial direction of the rotary shaft 9 because of a bottom face of the cup 8 fixed to the rotary shaft 9 by an axial direction end part 11g, and a holder 1 for restricting the movement in the other axial direction of the rotary shaft 9 by a restricting part 1r by butting at a plurality of points to the end part 8a of the cup 8 fixed to the rotary shaft 9.