PURPOSE: To obtain a probe for gap-size measurement at favorable costs.

CONSTITUTION: An eddy current loss type-distance sensor 11 is arranged on a bottom plate 12 inside a cylindrical case 10, a head 13 which can be slid along the inner circumferential face of the case is made to protrude from the upper face of the case, and two springs which are compressed when a head 13 is pressed and slid are stacked and interposed between the bottom plate 12 and the head 13. The spring constant of an upper-side spring 17 is set to be smaller than the spring constant of a lower-side spring 15, the length of the upper-side spring 17 is set to be longer than the length of the lower-side spring 15, and a conductor plate 16 which generates an eddy current by a changed magnetic flux generated by the eddy current loss-type distance sensor 11 is attached between both springs.