Each of additional members of a connector is provided with a connection mechanism. The connection mechanism is provided with a spring portion and a plate piece portion. The plate piece portion has an end face. The end face is formed with a connection portion. The connection portion is oriented inward of the connector in a second direction and located in a receiving portion at least in part. The spring portion supports the plate piece portion so that the connection portion is moveable in the second direction. When the connector is mated with a mating connector, the connection portion is connected to a mating connection portion.