To provide a compact drying and fermentation apparatus enabling continuous drying and fermentation without using a moisture adjusting material.

The drying and fermentation apparatus 11 has a hermetically closed vertical cylindrical shape and a partition plate 20 is formed to the central part thereof to respectively form a drying tank 12 and a fermentation tank 13 above and below the partition plate 20. A steam pipe 44 is arranged to the undersurface of the partition plate 20 and steam is introduced into the steam pipe to heat the partition plate 20. The matter 38 to be treated charged in the drying tank 12 is dehydrated by the heat of the heated partition plate 20 to be subjected to drying treatment so as to become a predetermined water content. The dried matter 38 to be treated is transferred to the fermentation tank 13 through a partition door 30 to be fermented by fermentation microorganisms and the composted treated matter is discharged to the outside from a discharge door 37.