A connector is provided which includes a housing in which a terminal is accommodated, and a retainer which is mounted on the housing to prevent movement of the terminal in the direction of detachment. A retainer insertion hole is provided on the housing to insert the retainer, and a provisional locking projection and a final locking projection are provided which extend into the retainer insertion hole. A guide portion is provided in the retainer which is flexibly deformed by interference from the provisional locking projection and the final locking projection, and a locked portion is formed, which is a locking hole opened in the guide portion. The locked portion and the provisional locking projection are temporarily locked during the insertion process, and the locked portion and the final locking projection are locked at the end of the insertion process.