PURPOSE: To obtain an article with high activity, also usable repeatedly because of being held in a state close to free enzyme in high concentrations at its central part protected by an outer skin layer, by specific treatment of an enzyme-contg. gelatin colloidal solution.

CONSTITUTION: Firstly, a porous reinforcing material is added to an enzyme- contg. gelatin colloidal solution followed by gelling the gelatin. Then, a crosslinking agent (e.g. an aldehyde such as glutaraldehyde) is made to act on the resulting gelatin gel in such a way as not to crosslink the gel at the central part but to crosslink only the gel in the outer skin region, thus obtaining the objective article containing a crosslinked gelatin gel shell layer 3 and uncrosslinked central part 4. The porous reinforcing material 2 is pref. a nonwoven fabric 0.01-0.1g/cm in denseness and 6-12 denier in the constituent fiber fineness, binder adhesion-treated with a water-insoluble resin. The solvent for the colloidal solution is pref. a buffer solution with the optimal pH value for the enzyme contained.