An object is to provide a more potent novel antimicrobial active substance, which is derived from a naturally occurring substance and has a broad antimicrobial spectrum, and an antimicrobial active substance DM0507 obtained by a production process comprising the following steps (a) to (d): (a) culturing Bacillus subtilis; (b) collecting the supernatant from the obtained culture; (c) collecting the precipitate formed by adjusting the pH of the supernatant to 3 or lower; and (d) performing extraction from the precipitate with ethanol is provided.