A connector includes: a port in which a disc configured to be displaceable is provided; a space defined by a side wall surrounding the disc in the circumferential direction when the disc is displaced and a bottom wall arranged at a position opposite the disc and configured to allow displacement of the disc; and a flow passage connected to the bottom wall at a position away from the side wall, and allowing fluid to flow therethrough to the space. The connector further includes cutouts formed from the flow passage to the side wall.