A biodegradable foam that excels in biodegradability, moldability and heat resistance and that even when utilized in food package containers, etc., ensures high safety; and a process for producing the same. There are further provided a biodegradable molding from the foam, and a process for producing the same. In particular, there is provided a biodegradable foam for sheet comprising a biodegradable foam obtained by mixing together rice husk powder, starch and a biodegradable thermoplastic resin and effecting foaming of the mixture and to be molded into a sheet form, characterized in that the foaming is carried out at a foaming ratio of 15-fold or below. Preferably, the biodegradable foam for sheet is characterized in that the mixture contains 5 to 40 wt. % of rice husk powder and 5 to 30 wt. % of starch. Further, it is preferred that the biodegradable thermoplastic resin be a mixture of two or more resin components with different melting points, and especially preferred that the extensity of resin with low melting point be greater than that of resin with high melting point.