A connection shell (23) includes a tubular fastener (25) formed by flat surfaces (25a) and curved surfaces (25b) and a rectangular tubular contact (24). A crimp ring (29) is crimped to fasten a wire shield (28) to the outer peripheral surface of the tubular fastener (25). The tubular contact (24) is connected so that a circumferential surface thereof overlaps a circumferential surface of a housing shell (19). The tubular contact (24) has a rectangular shape that conforms with the rectangular tubular shape of the housing shell (19). Thus, only a small clearance is defined between the housing shell (19) and the connection shell (23) to suppress leakage of noise through the clearance between the housing shell (19) and the connection shell (23).