So as to clarify the biodegradation mechanism of lignin, lignin biodegradability among four white-rot fungi, Pleurotus ostreatus 1,2,3, and Polyporus versicolor were compared each other by simple plate test method, so that P. ostreatus 2 and P. versicolor exhibited the most wide clear zone. And to investigate the degree of lignin depolymerization, they were grown in lignin­media where various carbohydrates were added, then that was analyzed through column chromato­graphy. In consequence, P. ostreatus 2 and 3 showed more excellent effect of lignin depolymerization among those 4 white-rot fungi, and also in culture media in which glucose, cellobiose and xylose were added. When culture filtrates of the same media were scanned at UV range, there were no peak at 280 nm in the culture filtrate of P. ostreatus 2 and 3 where glucose, cellobiose and xylose were added. At the same time, culture filtrate, in which lignin was only contained as a carbon source, showed browning in color, whereas culture media with glucose, cellobiose and xylose in addition to lignin became yellowish (that is, decolorization). From above results, it might be assumed that polymerization and browning of lignin were decreased and lignin biodegradability was increased, when grown in lignin media where various carbohydrates were added.