A novel convenient method for entrapping enzymes or microbial cells by the use of photo-crosslinkable resin prepolymer containing poly (N-vinylpyrrolidone) and ethyleneglycol dimethacrylate was described. Glucoamylase, used as test enzyme, was entrapped successfully and easily in the resin formed by the illumination with a Hg lamp. The relative activity of the glucoamylase entrapped in the resin was affected by the proportion of enzyme and prepolymers in the immobilization system. The entrapped glucoamylase showed about 4.5 times higher K_m value and about 2.5 times lower V_<max> value compared with the native glucoamylase (pH 4.5,35℃, substrate : maltose). The pH and temperature dependencies of the enzyme reaction were also compared between the entrapped and native glucoamylases.