Provided is a cooled optical transmission module device including a silicon wafer having a plurality of platform mounting grooves, each of which serves as a space for mounting in which an optical transmission platform therein, a thermoelectric cooler bonded to the platform mounting groove to transfer heat to outside, the optical transmission platform provided on the thermoelectric cooler and configured to output an optical signal by generating and reflecting the optical signal, a dielectric sub-mount bonded to the platform mounting groove of the silicon wafer and electrically connected to the mounted optical transmission platform, and a cover configured to cover the platform mounting groove of the silicon wafer and seal the platform mounting groove while providing an electric path.