A connector includes a housing having a flow path through which liquid passes, and a male connector connecting portion having a substantially circular tube hole communicating with the flow path； and a valve formed of an elastic material and adapted to block the male connector connecting portion of the housing. The valve includes a top surface exposed from the male connector connecting portion, a bottom surface opposite to the top surface, and a slit opened at least on the top surface or the bottom surface. The housing includes a stopping portion configured to be engaged with a tip end of a male connector to define an insertion length of the male connector.
