An engagement component that engages with the rear part of a sensor mounted to a sensor connector, and a manipulation body that moves this engagement component to a sensor insertion opening side are provided. In addition, there are provided a manipulation rod that is engaged at one end with the manipulation body and whose other end is pulled out of a main body case through a through-hole provided to the main body case, and a manipulation component that is linked to the other end side of this manipulation rod. The device further comprises an annular wall that is provided outside the main body case and around a through-hole, and a metal slide bearing that covers this annular wall, and a resin sliding member that is slid with respect to a metal slide bearing is provided on the metal slide bearing side of the manipulation component.
