The present invention herein provides a proliferation inhibitor of H. pylori bacteria comprising a compound that can specifically inhibit the proliferation of H . pylori bacteria, which does not generate bacterium resistant, can be eaten, drunken or administrated safely for a long period of time, can be simply mass-manufactured and can be used for foods and beverages or pharmaceutical preparation. The proliferation inhibitor of H. pylori bacteria comprises an N-acetylglucosaminyl beta-linked monosaccharide derivative represented by the following chemical formula (1): €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒGlcNAc1-beta-O-Y€ƒ€ƒ€ƒ€ƒ€ƒ(1) wherein Y is an alkyl group, an alkoxyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, a heteroaryl group, a carboxyl group or an alkoxycarbonyl group.
