A connector is constructed from a male connector having a cavity and a female connectorhaving a cavity to which the other male connector similar to the male connectorcan be connected. The connector has a male lock section and a female lock sectionto which the other male lock section similar to the male lock section can be coupled.When the connector is in a locked state where the female lock section and the othermale lock section are coupled, the female connector and the other male connectorare connected such that the cavities are communicated with each other to enableliquid to flow.