The purpose of the present invention is to breed a koji mold, which has improved capability of producing a variety of industrially applicable enzymes, without using the genetic recombination technology. By mutagenizing a strain belonging to the genus Aspergillus, a strain having a duplication of a large-scale genome region of 900 kb or more and is able to produce a variety of enzymes required in manufacturing soy sauce, for example, protease, etc. was obtained. This strain enables efficient production of various foods such as soy sauce.