PURPOSE: To form a roughage of indefinite shape into a suitable size, by compressing a roughage of indefinite shape or a mixture thereof prepared by adding water or an additive and uniformly mixing while stirring with two slat conveyors, etc., under pressure and drying the compressed roughage or mixture thereof.

CONSTITUTION: A fibrous roughage, e.g. fermented bagasse, etc., is suitably cut or pulverized if it is long or large and, as necessary, water or additive, e.g. concentrated feed, etc., is added and mixed therewith while stirring. The above-mentioned mixture (B) is then fed between two slat conveyors 18 and 19, etc., installed with facing transportation surfaces and having a wide spacing between the transportation surfaces on the inlet side and a narrow spacing between the transportation surfaces on the outlet side and the conveyors 18 and 19, etc. are driven to compress the mixture (B) into a sheetlike or matlike form under pressure. The resultant formed material is then dried. As a result, the roughage of indefinite shape can be formed into a suitable size to reduce the transportation and storage cost and facilitate the handling and feed collection. Furthermore, the growth of molds and deterioration can be suppressed at the same time.