An optical connecting device is disclosed including a first optical connector (50) having a plurality of hole groups formed of a first fiber through hole and a pair of first positioning pin holes (52a, 52b) provided in both sides of the first fiber through hole, and a first optical fiber (51a) inserted into the first through hole such that its connecting end surface is exposed, a plurality of second optical connectors (53, 54) having a second fiber through hole and a pair of second positioning pin holes (56a, 56b) provided in both sides of the second fiber through hole , and a second optical fiber (55) inserted into the second through hole such that its connecting end surface is exposed, and positioning pins (60a, 60b) inserted into first and second positioning pin holes, wherein the connecting end surfaces of the first and second optical connectors (50, 55) are brought into contact with each other, whereby the first and second optical fibers (51a, 55) are connected to each other.