To identify biologically active enzymatic components of the higher fungi in Korea, the dried carpophores of Cryptoderma citrinum was smashed with cool distilled water, extracted, salted out and the precipitate was purified by dialysing with visking tube and dissolved with pH 7.8 ammonia aqua. The fraction of the filtrate was lyophilized to obtain as light brown powder and then cellulase activity was determined. Cellulolytic potency of Cryptoderma citrinum was 750 unit/g. The optimum condition for the enzymatic reaction was pH 4.5 and $40^{circ}$. The enzyme activity was activated in the presence of $Ca^{2+}$, $Fe^{2+}$ and $Co^{2+}$.