The first connector body includes: a recess mating with the second connector body; a first side wall part extending in the longitudinal direction so as to define both sides of the recess; and a projection extending in the longitudinal direction of the recess so as to mate with a recessed groove of the second connector body, the first terminal includes a first contact part contacting the second terminal in a recessed groove between the projection and the first side wall part, the first connector further includes a shield plate which is held in the center in the width direction of the projection so as to extend in the longitudinal direction, the second reinforcing bracket includes a reference potential connection part connected to a reference potential trace; and a tongue part contacting both ends in the longitudinal direction of the shield plate, and the second connector further includes a reference potential terminal which includes a tail part connected to the reference potential trace along with a contact part contacting the middle of the shield plate in the longitudinal direction.