Abstract: A probe body (200) includes a middle closing portion (250) formed upright on a connector front portion (261A) and a female thread (261D) into which a male screw (110) is screwed. A sensor module (300) includes a slidable-contact portion (322) that slidably contacts with the connector front portion (261A), a pressing member (321) that is pressed against the middle closing portion (250) and an insertion hole (325). The insertion hole (325) has a widened portion (325B) that is inclined in such a manner that a distance between an opening on the pressing portion (321) side, the opening positioned on a screw-hole-forming-portion end surface (324), and the pressing portion (321) gradually becomes larger toward the slidable-contact portion (322) side. The insertion hole (325) has a diameter larger than that of the male screw (110).