A connector body includes mating guide parts having mating recesses into which counterpart mating guide parts are inserted, the reinforcing bracket includes a body part attached to end wall parts of the mating guide parts, and a pair of left and right connection arms connected to both ends of the body part, the connection arms extending to the longitudinal center of the connector body and being attached to side wall parts of the mating guide parts, the connection arm includes a side plate part and a side wall upper cover part connected to an upper end of the side plate part, at least a part of the outside of the side plate part is covered with an outside part of the side wall part, and the side wall upper cover part is curved such that a tip faces the mating recess and covers at least a part of the upper surface of the inside part of the side wall part.