A first connector (2) includes a first connector main body configured from an outer tube (4) of a cylindrical shape, an inner tube of a cylindrical shape, a hub (12) disposed at a proximal end portion of the outer tube (4), and a clip (13) disposed so as to be removable at the proximal end portion of the outer tube (4), a hollow needle supported on the hub (12), a first sealing member supported on the inner tube, a coil spring serving as puncturing portion biasing means for biasing the first sealing member toward the distal direction, and a clamping member disposed upon the outer tube (4). In a state in which the clip (13) is mounted to the proximal end portion of the outer tube (4), a protrusion (132) of the clip (13) engages with a protrusion (126) of the hub (12), and thereby rotation of the hub (12) is prevented. In addition, if the clip (13) is removed from the outer tube (4), the rotation of the hub (12) with respect to the outer tube (4) becomes possible.
