A connector includes inner conductors and an outer conductor. The outer conductor includes four plate portions surrounding outer peripheral surfaces of the inner conductors, a rear plate portion for closing a rear surface of the outer conductor and an opening provided behind the bottom plate portion and in front of the rear plate portion. The inner conductor includes a board connecting portion projecting outwardly of the outer conductor through the opening. The outer conductor includes a common base end portion connected to a rear end of the bottom plate portion via a bent portion and projecting toward the same side as the board connecting portion, and a plurality of branched pieces projecting from a projecting end of the common base end portion while being arranged in a width direction of the common base end portion.