PURPOSE: To arbitrarily select the direction and position of a probe for use and fasten the probe on the basis of the condition of a measurement position as an object for precise measurements undertaken with an indicator or the like.

CONSTITUTION: The direction and position of a probe 5 screwed and tightened to an internal thread 3" at the end of a spindle 3, are arbitrarily selected. Also, a fastening means has a nut 4 with an internal thread 4" engaged with a somewhat long and fine external thread 3' formed on the end section of the spindle 3. A nut 4 for rotating and lowering the base end 5' of the probe 5 screwed to the internal thread 3" at the end of the spindle is used to press and fix the probe 5 in the required direction and at the required position.