A connector includes a housing (10) that is connectable to a mating connector by rotating a lever (40) from an initial position to a connection position on the housing (10). The lever (40) has two arm plates (41) coupled by an operating portion (42). Ridge pieces (44) are on facing surfaces of the arm plates (41). Front and rear rails (22A, 22B) extend perpendicular to a pull-out direction of wires to guide the ridge piece (44) laterally. An introducing portion (26) is open on one end of the rear rail (22B) to receive the ridge piece (44) between the rails (22A, 22B) from a position behind the housing (10). An escaping portion enables the ridge piece (44) to rotate from a position between the rails to the position behind the housing (10) as the lever (40) is rotated from the connection position to the initial position.