With an attempt to obtain a glucose isomerizing enzyme producing microorganism, one hundred and thirty-three strains of microorganism were isolated from soil samples. After screening, a strain K-17 which belonging to actinomyces family, was finally selected. Using this strain of K-17, sugars produced from glucose by the reaction of sugar isomerizing enzyme were tested with paper chromatography. Only a kind of resulting sugar, fructose, was detected from enzyme reaction sample and other sugary were never detected. By these results, the enzyme produced by strain K-17 is classified as a glucose isomerase.