AN OBIECT OF THE PRESENT INVENTION IS TO PROVIDE A FERMENTED PRODUCT CONTAINING EQUOL-PRODUCING MICROORGANISMS IN THE STATE OF LIVING CELLS BY WHICH EQUAL PRODUCTION ABILITY IS MAINTAINED.WHEN PRODUCING A FERMENTED MATERIAL BY USING AN EQUOL-PRODUCING MICROORGANISM, WITH SOYBEAN POWDER OR SOYBEAN MILK AS RAW MATERIALS, (1) PREPARING A MOTHER STARTER BY FERMENTATION UNDER ANAEROBIC CONDITIONS BY USING AN EQUOL-PRODUCING MICROORGANISM IN THE PRESENCE OF A DAIDZEIN SPECIES AT pH 5.0 OR HIGHER, (2) PREPARING A BULK STARTER BY FERMENTATION UNDER ANAEROBIC CONDITIONS BY USING SAID MOTHER STARTER IN THE PRESENCE OF A DAIDZEIN SPECIES AT pH 50 OR HIGHER, AND (3) PREPARING A FERMENTED MATERIAL BY FERMENTATION BY USING SAID BULK STARTER IN A MEDIUM CONTAINING SOYBEAN POWDER OR SOYBEAN MILK, ENABLES PRODUCTION OF A FERMENTED MATERIAL CONTAINING MICROORGANISMS IN THE STATE OF LIVING CELLS IN WHICH THE EQUOL PRODUCTION ABILITY IS MAINTAINED.
