A first male member (110) and a tubular portion (30) are in communication via first to third holes (21 to 23). A liquid channel (211) and a gas channel (212) of the second male member (210) are in communication with the tubular portion. First to third channels (41 to 43) are formed in a stopcock (40). The stopcock can switch between a first rotation position at which the first channel puts the first hole and a syringe connection portion (32) of the tubular portion in communication, and a second rotation position at which the first channel puts the liquid channel and the syringe connection portion in communication. When the stopcock is at the second rotation position, the second hole and the gas channel are in communication via the second channel, and the first male member and an inner cavity (45) of the stopcock are in communication via the third hole and the third channel. A first hydrophobic filter (50a) is provided in the channel that connects the first male member and the gas channel when the stopcock is at the second rotation position, and a second hydrophobic filter (50b) is provided in the channel that connects the first male member and the air supplying member (410) that is connected to the stopcock when the stopcock is at the second rotation position.