A connector (10) includes: a port (28) in which a disc (36) isprovided a space (76) having a side wall (76a) surrounding displacement of the disc (36) in the circumferential direction and a bottom wall (59) arranged at a position opposite the disc (36) and capable of allowing displacement of the disc (36) and aflowingpart (50) connected to the bottom wall (59) ataposition away from the side wall (76a), and allowing fluid to flow therethrough to the space (76). The connector (10) further includes cutouts (96, 97, and 98) formed from the flowing part (50) to the side wall (76a).
