Optical transmission moduleOptical element 10 andAn optical fiber 20 which is a reflective surface 20sa having an end surface inclinedA retaining member 40 having an end portion of the optical fiber 20 embedded thereinAn optical element 10 is mounted on the first main surface 50sa, and the holding member 40 is adhered to the second main surface 50sb, and a wiring board 50 having a through hole H50 serving as an optical path is formed.AndThe holding member 40 is made of transparent resin.The bottom surface 40sa of the holding member 40 abuts against the second main surface 50sb of the wiring boardThe angle. Theta. Of the reflecting surface 20sa with respect to the main surface 10sa of the optical element 10 is fixed at an angle at which light transmitted through the optical fiber 20 is coupled to the optical element 10.光伝送モジュール1は、光素子10と、端面が傾斜している反射面20SAである光ファイバ20と、光ファイバ20の端部が埋め込まれている保持部材40と、第1の主面50SAに光素子10が実装されており第2の主面50SBに保持部材40が接着されており光路となる貫通孔H50が形成されている配線板50と、を具備し、保持部材40が透明樹脂からなり、保持部材40の底面40SAが配線板50の第2の主面50SBと当接し、反射面20SAの光素子10の主面10SAに対する角度θが光ファイバ20を導光される光が光素子10と光結合する角度に固定されている。