PURPOSE: To perform a precise measurement over a wide range by a method wherein a measuring probe is attached to a member for a parallel motion mechanism and the measuring probe is moved in parallel.

CONSTITUTION: A turning and moving shaft 26 is turned and moved in a prescribed direction, and a measuring-probe holding member 12 is pressurized by a pressurization arm 29. Then, a tip ball 16a for a measuring probe 16 is brought into pressure contact with an object S to be measured, and a measuring pressure is exerted on the measuring probe 16. When the object S is moved arbitrarily on a surface plate 30 in this state, the displacement amount in the up-and-down direction of the measuring probe 16 is detected precisely by a displacement detector according to a change in the height of the object S. The member 12 is moved in parallel in the up-and-down direction by the same amount with reference to the up-and-down movement of the measuring probe 16, and the amount appears as it is as the displacement amount of the scale 20 which has been fixed and bonded to the member 12. On the other hand, since a detection head 21 is not moved and the same displacement as the displacement amount of the measuring probe 16 is caused between the head 21 and the scale 20. As a result, the displacement amount of the measuring probe 16 can be detected precisely by the relative displacement between the scale 20 and the head 21. In addition, since the measuring probe is moved in parallel with a base member 6, a long stroke can be obtained.