PURPOSE: To undertake measurements in the 360-degree range of directions orthogonal with a measurement needle and in a vertical direction by vertically providing the needle on an approximately semicircular projection formed on the principal plane of an approximately disc form substrate, and laying the needle within a circular recess section allowing loose insertion.

CONSTITUTION: An approximately disc form substrate 31 made of hard material 37 is loosely inserted in the circular recess 41 of a hard member 47, and a measurement needle 34 is coupled to the insertion hole 43 of the member 47. An approximately semicircular projection 33 formed at the center of the principal plane of the substrate 31 is movable, while being in contact with the taper 44 of the hole 43. Also, the disc form end 51 of hard material 52 is energized with a coil spring 49 and, therefore, always adheres to the surface of the substrate 31. Furthermore, the needle 34, when not subjected to other stress, is positioned perpendicularly to the bottom surface 42 of the member 47. When the needle 34 is deformed due to external stress in any direction vertical thereto or within a 360-degree range, the substrate 31 is also inclined with the inclination of the needle 34 and pushes a member 52 about the taper 44 as a support point against spring stress. Thus, the member 52 pushes the measurement needle 5 of a gauge 20 toward a measurement direction, with the rod form rear end 53 thereof in contact with the needle 5.