To enable each optical connector provided to a substrate to be protected and the handling of optical connectors provided to the substrate to be facilitated.SOLUTION: The present invention comprises: a plurality of flanged tubular members having a tubular body part and a flange part provided at one end of the tubular body part; a plurality of optical connectors inserted from the flange part side of each flanged tubular members toward the other end of the tubular body part, with the tip part located on the tubular body part side; and a substrate having a plurality of open holes provided in the thickness direction of the substrate. The tubular body part of each flanged tubular member having each optical connector inserted therein is removably inserted into each open hole of the substrate, with the flange part coming in contact with the periphery of the open hole and supporting the flanged tubular member. Each optical connector and the flange tubular member having each optical connector inserted therein are fixed in position.SELECTED DRAWING: Figure 1