This invention provides an optical transmission module that is of low cost and that can be mounted even in a narrow space. An optical transmission module of the present invention includes a light reception processing section for converting an optical signal transmitted by an optical wiring to an electric signal, a reception side substrate part including an electric wiring for transmitting the electric signal, and a reception side connector section for providing the electric signal to the light reception processing section and the reception side substrate part. The light reception processing section and the reception side connector section are mounted on a same substrate surface of the reception side substrate part, and the reception side substrate part includes a bending portion bent so that the substrate surfaces oppose each other at the back in the normal direction.