[Problem] To provide a nucleic-acid-containing, soy-sauce-like flavoring that contains a high concentration of nucleic acids that are only 5'-nucleotides derived from fermentation, without adding 5'-nucleotides from outside, and also provide a production method therefor. [Solution] Said problem is solved by this production method for a fermented flavoring, said method comprising: a step in which a grain feedstock having soybeans, wheat or the like as the main feedstock thereof is inoculated with a koji mold to prepare solid koji, water or salt water is added thereto, and the resulting moromi having a salt concentration of 4% (w/v) or less is heated and broken down； a step in which the moromi is heat-treated and phosphatase is deactivated so as to prepare sterilized moromi； a step in which the sterilized moromi is inoculated with nucleic-acid-producing microorganisms, and nucleic acid fermentation is performed in a container capable of suppressing the inmixing of harmful microorganisms； a step in which the nucleic-acid-producing microorganisms undergo self-digestion and RNA in the microorganisms is released into the moromi so as to prepare an RNA extract； and a step in which nuclease and deaminase act on the RNA extract to convert the RNA extract into flavorful 5'-nucleotides.Le problème décrit par l'invention est de fournir un arôme de type sauce de soja contenant des acides nucléiques qui contient une concentration élevée d'acides nucléiques qui sont uniquement des 5'-nucléotides dérivés de la fermentation, sans ajouter de 5'-nucléotides de l'extérieur, et également un procédé de fabrication associé. La solution selon l'invention porte sur un procédé de fabrication d'un arôme fermenté, ledit procédé comprenant : une étape à laquelle une charge d'alimentation de céréales présentant du soja, le blé ou analogue en tant que sa charge d'alimentation principale est inoculé avec un moule koji pour préparer un koji solide, de l'eau ou de l'eau salée y est ajoutée, et le mo
