PURPOSE: To provide a non-contact type displacement apparatus having a simple structure capable of maintaining vertical position of a displacement meter with high accuracy.

CONSTITUTION: The apparatus is provided with a sub-reciprocating drive device 2 that moves a non-contact type displacement meter 4 in a direction perpendicular to a scanning direction (Y axis direction) and rotates the displacement meter 4 around the Y axis while it is moved in the scanning direction. The sub-reciprocating drive device 2 is horizontally supported so that the movement in the Y axis direction and rotation around the Y axis can be carried out. It comprises a main shaft 5 on which a screw groove and a spline groove are formed on a circumferential surface thereof, a ball screw nut meshed with the screw groove of the main shaft 5, a ball spline nut meshed with the spline groove of the main shaft 5 and a first driving mechanism 6 and second drive mechanism 7 each independently driving the respective nuts. The displacement meter 4 is attached to a tip section of the main shaft 5.