A connector having a housing, a slide member, and an operation lever. The slide member slides in response to operation of the operation lever. The slide member has a guide projection and slides while the guide projection is guided in a guide groove of the housing. The slide member has a cam groove that receives a cam pin in a second connector and the slide member, by sliding, performs mating with the second connector. The slide member has a first nipping portion that nips the cam pin when it slides to a completely mated position. The housing has a second nipping portion that nips the guide projection of the slide member when the slide member slides to the completely mated position.