PURPOSE: To obtain a two-way touch sensor which has excellent air-tightness and a high dustproof effect by constituting a probe shaft of the 1st shaft material disposed in the outside of a body and the 2nd shaft material disposed in the body.

CONSTITUTION: When a touch sensor is lowered to bring a measuring element 21 into contact with a measuring surface, a probe shaft 19 oscillates counterclockwise around a fulcrum shaft 15, and a lever 29 positioned on the upper side of a contactor 23 oscillates to a turning body 35 side and contacts with the body 35. Then a switch 41 is closed to light a display element 5, at the same time, a contact signal is transmitted through a plug 52 to the control section of a measuring machine. The shaft 19 is held hermetically closed at the shaft 15 and since the hermetic state of a through-hole 26A is intensified by a collar part 15A, an excellent dust-proofing effect is assured.