An optical module has a support board, an optical transmission path, and at least a single optical element having a light receiving function or a light emitting function provided on the support board. A light emission surface of the optical transmission path or a light incidence surface of the optical transmission path is arranged such that the optical element and the optical transmission path are optically coupled to each other, with respect to a light receiving surface or a light emitting surface of the optical element. The optical element is sealed by a sealing agent. A gap is provided between the optical transmission path and the surface of the sealing agent on the light receiving surface or the light emitting surface of the optical element.