Measurement probe and using method for the same

A measuring probe, comprising:

• a housing configured to be made of a magnetic material in a cylindrical shape;
• a movable member configured to be provided inside the housing along an axis line of the housing, the movable member having a contact portion at one end configured to come into contact with a measuring target face and a reflecting plane formed at the other end configured to reflect a measuring light beam, and being made of a nonmagnetic material in a rod shape;
• a magnetic substance configured to be mounted on the movable member;
• a bearing made of a magnetic material which is in a cylinder shape with the movable member running through at a center portion, the bearing configured to be press-fitted into the housing and support the movable member movably in axis line direction in a non-contact state;
• a magnetic force generating portion configured to be in a cylinder shape with the movable member running through at a center portion and be fitted into the housing, the magnetic force generating portion having a retreat magnetic force generating portion configured to work on the magnetic substance of the movable member and move the movable member toward retreat direction along the axis line direction, and a measurement magnetic force generating portion configured to work on the magnetic substance of the movable member and move the movable member toward measuring direction along the axis line direction;
• and
• a cover member configured to be mountable on and demountable from the housing, prevent the magnetic force generating portion and the movable member from dropping off from the housing, and be made of a magnetic material.