An incorrect fitting of a connector (40) is prevented, and a fitting work is enabled to be performed smoothly. A plurality of connectors (40), each having a housing (41) capable of fitting with its counterpart housing (71), is arranged in a line. Upon fitting of the housings (41, 71), a front face of each housing (41) is arranged so as to face a direction facing its counterpart housing (71), and an aligning direction of the connectors (40) is set to be a direction intersecting a front-rear direction. Through portions (52, 52E) are provided in the housings (41), and upon fitting of the housings (41, 71), each connector (40) is arranged at a position capable of facing its counterpart connector (70) by an aligning member (80, 100) that is passed through the respective through portions (52, 52E).