A connector body includes a recess, a middle island inside the recess, and a mating guide part formed on both sides in the longitudinal direction; a reinforcing metal bracket includes a main body part disposed on the end wall part of the mating guide part, and a central guide part which is connected to the main body part and has a tip which engages with the island end part of the middle island; and the central guide part includes an end wall inner cover part connected to the main body part, an island end cover part which is connected to the tip and covers at least a portion of the island end, and a bottom part which is connected to a lower end of the end wall inner cover part via a first curved part and is connected to a lower end of the island end cover part via a second curved part; wherein a lower surface of the first curved part is positioned above a lower surface of the second curved part.