An optical transmission module includes: an optical device having a light emitting section that outputs light of an optical signal; an optical fiber that transmits the optical signal; a holding member in which a distal end portion of the optical fiber is inserted into a through hole having an inner diameter equivalent to an outer diameter of the optical fiber, and that is disposed on the optical device; and a lens section that is disposed in an opening on the optical device side of the through hole of the holding member, and that concentrates the light.