In this study, the production characteristics of pyranonigrin-A by sixteen Aspergillus strains using rice koji, barley koji, and buckwheat koji were investigated. Results showed that A. oryzae had little capacity for producing pyranonigrin-A. In contrast, it was found that A. luchuensis had a production capacity for pyranonigrin-A. In addition, it was estimated that the difference between DPPH radical-scavenging activities A. oryzae and those of A. luchuensis depended on the difference in the production of pyranonigrin-A. More pyranonigrin-A could be produced by using buckwheat for raw materials rather than rice or barley. It was clarified that the difference in the amount of pyranonigrin-A by shochu-koji fungi depended on the difference of the pyranonigrin-A production per conidial production and unit conidium.