To provide a technology for flexibly modifying terminal configurations in electrical connectors, the present disclosure involves a plug connector that includes a housing and multiple terminals held in place in the housing, wherein the housing includes a main body portion, in which the multiple terminals are arranged, and first exterior wall portions and second exterior wall portions, which are provided at both ends of the main body portion; the first and second exterior wall portions extend in a direction perpendicular to the array direction of the multiple terminals; the first exterior wall portions include a first coupling portion at the end in a first extension direction; the second exterior wall portions include a second coupling portion at the end in the same direction as the first extension direction; and the first coupling portion and the second coupling portion have mutually engageable shapes.