A connector includes a male connector section having a male-side cavity, a female connector section having a female-side cavity to which another male connector section the same as the male connector section can be connected, a seal member formed from an elastic material for maintaining liquid tightness between the connector sections when the other male connector section and the female connector section are connected to each other, and lock mechanisms disposed respectively on the male connector section side and the female connector section side for maintaining the connected condition of the connector sections when the other male connector section and the female connector section are connected to each other. Each of the lock mechanisms has a male lock section formed to project in parallel to the direction of connection between the connector sections, and a female lock section, which is formed adjacent to the male lock section and parallel to the direction of connection, and to which another male lock section the same as the male lock section can be coupled.
