The enzyme activities of Phoma Wasabiae were studied. Activities were measured by the use of the enzyme suspension without purification. It turned out that the mold had polyphenol oxidase and peroxidase activities. Therefore，it has been recognized that the enzyme activities of Phoma Wasabiae resemble the activities of Ceratocystis fimbriata. It is thought possible that this polyphenol oxidase activity is allowed to change color of the root−stock of Wasabi and the culture solution of potato.