Today oligosaccharides are widely used in food, drug and cosmetics production. Enzymatic hydrolysis of polysaccharides is one of the prospective ways of oligosaccharide production. This work studies kinetic regularities of xylan hydrolysis using free and immobilized xylanase enzyme produced by Ð¢richoderma viride (endo-1,4-D-xylanase, EC 184.108.40.206). The analysis of kinetic regularities and values of rate constants suggests a hypothesis about some peculiarities of the mechanism of xylan hydrolysis with a free and immobilized enzyme complex. The hypothesis on the insignificant effect of the immobilization on the enzyme complex activity was proposed. The synthesized catalytic system is reusable (at least 10 runs) and can be used for plant glycan hydrolysis to produce oligosaccharides of various polymerization degree.