An optical connecting device including an optical waveguide substrate having a plurality of optical waveguides, at least two fiber arranging members connected to at least one connecting end surface of the optical waveguide substrate, and an optical fiber disposed in the position controlling means of the fiber arranging members, wherein the connecting end surfaces of the optical wave guides and the optical fiber are brought in contact with each other, thereby the optical waveguides and the optical fiber are optically connected to each other. An optical connecting device including a first optical connector having a plurality of hole groups formed of a first fiber through hole and a pair of first positioning pin holes provided in both sides of the first fiber through hole, and a first optical fiber inserted into the first through hole such that its connecting end surface is exposed, a plurality of second optical connectors having a second fiber through hole and a pair of second positioning pin holes provided in both sides of the second fiber through hole, and a second optical fiber inserted into the second through hole such that its connecting end surface is exposed, and positioning pins inserted into first and second positioning pin holes, wherein the connecting end surfaces of of the first and second optical connectors are brought into contact with each other.