<p>An object of the present invention is to prevent a housing from being fitted into a receptacle in a wrong posture. <??>A female connector 10 is provided with a lever 40 in the form of a single plate, and this lever 40 is locked at an initial position by a resilient locking piece 46 before a connecting operation of the female connector 10 with a male connector 50. An unlocking rib 55 for canceling a locked state effected by the resilient locking piece 46 upon the connecting operation projects at a position of the ceiling surface of a receptacle 53 of the male housing 50 near one side. An insertion preventing rib 56 projects from the inner surface of the receptacle 53 at a side opposite from the unlocking rib 55, and an escape groove 47 for receiving the insertion preventing rib 56 is formed in the upper surface of the lever 40. Thus, the female connector 10 can be prevented from being inserted in a wrong posture into the side of the receptacle 53 where the unlocking rib 55 is not provided. <IMAGE></p>
