A connector to be connected to a mating connector, includes a connector main body including a cylindrical member, a supporting member disposed in the cylindrical member, a terminal supported on the supporting member, and a fitting portion having an engaging portion; a movable sleeve including a diameter control portion; an elastic deformation member disposed to be elastically deformable in a radial direction thereof; an accommodating portion disposed between the connector main body and the movable sleeve for accommodating the elastic deformation member; and a transmission unit for transmitting a force in the axial direction from the movable sleeve to the elastic deformation member when the movable sleeve moves, and for transmitting a force in the radial direction from the elastic deformation member to the movable sleeve when the elastic deformation member returns to an original shape.