In order to study the enzymatic properties of human type tubercle bacilli, H37 Rv, H37 Ra and BCG, and avian type bacilli, Takeo's strain, Myc. ATCC 607 and Myc. phlei, the auther prepared the soluble fraction and particulate fraction of these cells by means of ultracentrifuge frnm the ground cells that were cultured in Sauton's media. Using the fractions thus obtained, the author observede nzyme activities of these fractions. And then, the author picked out the soluble fraction of H37 Ra; dialyzed it and studied the dehydrogenase activity of the dialyzed soluble fraction for lactate and malate with the addition of Cofactor by means of Thunberg's methylen blue reduction method. The following results were obtained. 1) It was observed that the enzyme activities of two fractions, soluble and particulate, were distinctly different in any organisms. 2) It could be comfirmed that the specilic enzyme activity of each fraction for ehe substrates and the intensities of that activities were varied as the strains. 3) The dehydrogenase activity of the dialyzed soluble fraction of H37 Ra for lactate was raised by the addition of CoI. And riboflavin could substitute for CoI. 4) The more increased dehydrogenase activity for malate was observed by the simultaneous addition of GoI and riboflavin to the dialyzed soluble fraction of H37 Ra compaired with the single addition of CoI to that fraction. However riboflavin failed to replace the role of CoI.