A protein having a novel saccharide oxidase activity capable of being subjected to various uses is provided. The present invention provides a protein having the following physicochemical characteristics: (1) effect: oxidizing a saccharide to produce a saccharic acid； (2) substrate specificity: acting on glucose, maltotriose, maltose, galactose, maltotetraose, lactose, and cellobiose； and, (3) [Km value of glucose]/[Km value of maltose]≦1.
