Abstract: A foamable resin composition according to the present invention comprises 10 parts by weight or less, preferably 0.5 to 8 parts by weight of a biodegradable resin and/or polyolefin resin, 10 to 30 parts by weight of water and 0.01 to 5 parts by weight of an inorganic filler, with respect to 100 parts by weight of a modified starch. The modified starch is preferably at least one of oxidized starches, esterified starches, acetylated starches and cationic starches. The foamable resin composition can maintain strength, etc., of the foamed body obtained at a practical level even though the amount of the biodegradable resin and/or polyolefin resin is reduced as much as possible, and has a cost advantage.