A connector assembly is provided with a first connector having an outer tube and an inner tube, the outer tube being equipped with a pin having a first flow path, the inner tube being equipped with a first valve element for opening and closing a the first flow path a second connector having a second flow path and a second valve element for opening and closing the second flow path a locking means for interconnecting, in an assembled state in which the first and second connectors are assembled together, the inner tube and the second connector and an unlocking means for unlocking the connection between the inner tube and the second connector effected by the locking means. The first flow path and the second flow path are interconnected in the assembled state. In this interconnected state, the connection between the inner tube and the second connector by the locking means cannot be unlocked by the unlocking means.