An optical printed circuit board comprising: an insulating layer ; an optical wave guide buried in the insulating layer to transmit an optical signal and including: - a first region parallel to a top surface or a bottom surface of the insulating layer , - a second region extending from one end of the first region and having a predetermined curvature of an obtuse angle, and - a third region extending from the other end of the first region and having a predetermined curvature of an obtuse angle; and an optical path converting part provided on the second and third regions of the optical wave guide to convert a transmission path of the optical signal defined by the optical wave guide such that the transmission path has the predetermined curvature of the obtuse angle, wherein the optical path converting part comprises: a first optical path converting part provided at the second region of the optical wave guide to keep a first end of the optical wave guide at the obtuse angle, and a second optical path converting part provided at the third region of the optical wave guide to keep a second end of the optical wave guide at the obtuse angle, characterized in that the first and second optical path converting parts are formed of a material different from a material for the insulating layer , and wherein the first and second optical path converting parts are formed of a thermosetting insulating material having a glass transition temperature higher than that of the material for the insulating layer . an insulating layer ; an optical wave guide buried in the insulating layer to transmit an optical signal and including: - a first region parallel to a top surface or a bottom surface of the insulating layer , - a second region extending from one end of the first region and having a predetermined curvature of an obtuse angle, and - a third region extending from the other end of the first region and having a predetermined curvature of an obtuse angle; and - a first region parallel to a top surface or a bottom surface of the insulating layer , - a second region extending from one end of the first region and having a predetermined curvature of an obtuse angle, and - a third region extending from the other end of the first region and having a predetermined curvature of an obtuse angle; and an optical path converting part provided on the second and third regions of the optical wave guide to convert a transmission path of the optical signal defined by the optical wave guide such that the transmission path has the predetermined curvature of the obtuse angle, wherein the optical path converting part comprises: a first optical path converting part provided at the second region of the optical wave guide to keep a first end of the optical wave guide at the obtuse angle, and a second optical path converting part provided at the third region of the optical wave guide to keep a second end of the optical wave guide at the obtuse angle, a first optical path converting part provided at the second region of the optical wave guide to keep a first end of the optical wave guide at the obtuse angle, and a second optical path converting part provided at the third region of the optical wave guide to keep a second end of the optical wave guide at the obtuse angle, characterized in that the first and second optical path converting parts are formed of a material different from a material for the insulating layer , and wherein the first and second optical path converting parts are formed of a thermosetting insulating material having a glass transition temperature higher than that of the material for the insulating layer . <EOS>