To provide an optical module capable of miniaturization, the optical module, to which an optical plug provided at one end of an optical transmission path is attached, so as to transmit and receive signal light via the optical transmission path for information communication, includes: a transparent substrate having light transmittance property with respect to a wavelength of used signal light; an optical socket, which is arranged on one surface side of the transparent substrate and to which the optical plug is attached; an optical element, which is arranged on the other surface side of the transparent substrate and emits the signal light to the one surface side of the transparent substrate according to a supplied electrical signal, or generates an electrical signal according to the intensity of the signal light supplied from the other surface of the transparent substrate; and a reflective portion, which is arranged on the other surface of the transparent substrate and changes a path of the signal light emitted from the optical element at substantially 90 degrees to guide it to the optical transmission path, or changes a path of the signal light emitted from the optical transmission path at substantially 90 degrees to guide it to the optical element.