[PROBLEMS] To provide a seed koji for brewing, which is suitable for wheat allergy patients and wheat intolerance patients (patients with celiac disease) and the medium of which is completely free from wheat-origin component, a koji for brewing, brewed foods and a method of producing the same. [MEANS FOR SOLVING PROBLEMS] Whole soybeans are hulled. A koji mold belonging to the genus Aspergillus is inoculated into the soybean hull thus obtained and cultured therein to give a solid seed koji. By using this seed koji, brewed foods (for example, soy sauce, miso, a liquid seasoning and so on) free from wheat-origin component are produced. Thus, it is possible to obtain a seed koji which is free from wheat-origin component, shows a high sporulation rate of the koji mold and has excellent koji-making properties. Use of this seed koji makes it possible to produce brewed foods which are comparable in qualities to the brewed foods produced by using a seed koji which has been cultured in a wheat medium.