A rapid fermented type salt-free Miso-like food material which is favorable in taste and flavor, which has a strong umami, rich taste, thickness, and mouthfullness, and a reduced stuffy smell or astringent taste may be prepared in a method including: adding a Koji mold and a bacteriocin-producing lactic acid bacterium culture fluid or a supernatant thereof to a food material; making Koji in a hermetically sealed Koji-making equipment while continuously or intermittently supplying clean air; mixing the bacteriocin-producing lactic acid bacterium culture fluid or the supernatant thereof with the thus-resulting Koji, and further mixing one or more food materials as needed in an amount of 0.01 to 50 times weight of the Koji; forming a moromi-mash by making a paste from the mixture; and then hydrolyzing the moromi-mash in the absence of common salt, by adding any one of an alcoholic liquor, yeast, and dextrin to the Koji.