The optical transmission module 1 guides the first optical signal L1 incident from the upper surface 10sa and directs the optical waveguide plate 10 for emitting the light transmitted second optical signal L2 from the upper surface 10sa, and the light emitting element 20 for generating the first optical signal L1, and the second optical signal The light receiving element 30 for receiving the optical signal L2 of the optical signal L2, the light emitting element 20 and the light receiving element 30 are mounted on the first main surface 40sa, and the second main surface 40sb is disposed on the upper surface 10sa of the optical waveguide plate 10, and the wiring board 40 made of a light transmitting material is formedA shading wall 49 is formed between the light emitting portion 44 and the incidence portion 42 of the wiring plate 40 to which the first optical signal L1 is incident and the outgoing portion 44 of the second optical signal L2 to be emitted.光伝送モジュール1は、上面10SAから入射する第1の光信号L1を導光するととともに、導光した第2の光信号L2を上面10SAから出射する光導波路板10と、第1の光信号L1を発生する発光素子20と、第2の光信号L2を受光する受光素子30と、第1の主面40SAに発光素子20および受光素子30が実装され、第2の主面40SBが光導波路板10の上面10SAに配置されている、光透過性材料からなる配線板40と、を具備し、配線板40の第1の光信号L1が入射する入射部42と第2の光信号L2が出射する出射部44との間に、配線板40の内部を導光される光を遮断する遮光壁49が形成されている。
