There is provided a probe including a connector whose end portion constitutes a connection end surface, a first cover for covering the side of the connection end surface of the connector, which is constituted by a surface perpendicular to a first direction expressing the direction toward which the aforementioned probe is inserted, anda second cover which is constituted movably toward a second direction expressing the direction opposite to the first direction and which covers the connector by being stretched from the outer circumference of the first cover toward the second direction. Here, the second cover moves toward the second direction by receiving a press force directed toward the second direction from a wall surface formed with an opening of the adapter unit at the time of insertion of the connector into the adapter unit. In addition, the first cover is constituted so as to be broken by the connector s press force directed toward the first direction in a case in which the second cover moves toward the second direction.
