An optical backplane connector with a board removable (being possible to insert and remove) therein in the direction perpendicular to the backplane plate surface is arranged on a backplane having optical transmission paths. The optical backplane connector accommodates a photoelectric conversion module in such a manner the incident and exit light are perpendicular to the backplane and a transparent board with a photoelectric conversion element mounted thereon is perpendicular to the board and parallel to the backplane. The conduction between the electric contacts of the photoelectric conversion module and the inner electric contacts of the optical backplane connector is held by mechanical contact. At the end portion of the optical transmission path on the backplane, an optical connector having a 45′ mirror and guide pins is mounted. The positioning operation is achieved by fitting the guide pins of the optical connector with the guide holes of the photoelectric conversion module.