A locking member is inserted into a cavity portion in a housing, and the side walls of the locking member are used to constitute part of the outer wall of the terminal accommodating chamber. On the inner surfaces of first locking projections respectively provided on the one-end-face sides of the present two side walls, there are projectingly provided guide ribs so as to extend in parallel to the insertion direction of a connecting terminal. When inserting the connecting terminal into the terminal accommodating chamber, even in case where the connecting terminal is inserted in an inclined manner, the connecting terminal is guided by the guide ribs and the inclination thereof is corrected by the guide ribs, whereby the connecting terminal can be inserted smoothly and the leading end of the connecting terminal is prevented from interfering with the terminal accommodating chamber, the locking member, first locking projections.