To provide a heat treatment unit for granular feeds for domestic animals, which can completely sterilize the feed stock, even when it is partly infected with salmonella or the like, and gives granular feeds which are sufficiently fluid even when taken out from a silo on a farm, can be fed without producing dust, and can be evenly mixed, as required, with a stock by-passed around the heat treatment because of its insufficient resistance to heat.

This heat treatment unit 1 is provided with an injection port 31 and discharge port, and also with a slanted tubular casing 3, which is closed at the upper and lower ends by side plates 33 and 34, provided with a plurality of openings 35 thereon, each of which is connected to a nozzle for injecting steam or an auxiliary liquid material, and also provided with a rotating axis therein, on which a plurality of blades are set at intervals to agitate steam, wherein the rotating axis are supported by the side plates 33 and 34 at both ends, driven by a driving means, and the discharge port is connected to a discharged quantity adjusting unit 2 which works to adjust residence time of the feed guided into the tubular casing 3.