One end of a tubular portion (16) is sealed with a stopcock (5) that is fitted in the tubular portion (16). A first flow channel (33) and a second flow channel (36) are formed in the stopcock (5). A first hole (37), a second hole (43), a third hole (38), and a fourth hole (44) are formed in a connector main body (2). Switching between a setting that brings an inner space (16a) of the tubular portion (16) into communication with the first hole (37) via the first flow channel (33) and a setting that brings the inner space (16a) of the tubular portion (16) into communication with the second hole (43) via the first flow channel (33) and brings the third hole (38) into communication with the fourth hole (44) via the second flow channel (36) can be achieved by rotating the stopcock (5).