PROBLEM TO BE SOLVED: To provide a soybean-rice bran fermented composition, which has in vivo ACE inhibitory activity equal to that of a conventional synthetic ACE activity inhibitor to suppress rise in blood pressure for preventing/ameliorating hypertension, and achieves a high level of safety with no adverse effect at low cost； a method of producing the soybean-rice bran fermented composition； and an antihypertension composition and diet.SOLUTION: The soybean-rice bran fermented composition is obtained by treating a fermentation product, which is prepared by fermenting at least a soybean protein/soybean proteins and rice bran, with a protease/proteases. The method of producing the soybean-rice bran fermented composition, and the antihypertension composition and diet are also provided. Preferably, the fermentation product is prepared by fermentation using at least one of Bacillus natto, Rhizopus oligosporus, lactic acid bacteria and yeast.
