Abstract: The present invention comprises a waste-bio-fermenter device based on temperature control by means of heating and cooling an added liquid or gaseous solution, for energy-use optimization. The device makes it possible to utilize, for energy purposes, biomass and gases that result from anaerobic biodigestion in the thermophilic phase, said device differing from biodigesters currently offered in the market in that its temperature control is monitored, resulting in a shorter fermentation time, better quality, for energy-use purposes, of the produced dry material, and a high yield. The waste bio-fermenter has an elongate form and is built in a metallic structure comprising double partition lateral walls, sloping bottom to allow the solution runoff, and a ceiling with a hatchway. In the space between the partition walls heating of the liquid or gaseous solution placed therein occurs and then the heat present in the solution is transmitted to the internal cell.