It is intended to provide base sequences participating in the regulation of the expression of a promoter. It is also intended to modify a promoter based on the base sequence data to give a modified promoter having a high expression activity. Namely, a modified promoter constructed by inserting a first DNA fragment containing CCAATNNNNNN (SEQ ID NO:1) (a first base sequence) and a second DNA fragment containing CGGNNNNNNNNNGG (SEQ ID NO:2) (a second base sequence) into a promoter functioning in a filamentous fungus, wherein N in the base sequence denotes A (adenine), G (guanine), C(cytosine), or T (thymine).