Abstract: It is intended to provide lectins and a lectin library comprising these lectins which are useful in recognizing differences in carbohydrates on cell surface (for example, sugar chains and cell surface glycoproteins) reflecting extremely subtle differences among cells, etc. and thus distinguishing, identifying or fractionating various cells.

Abstract: It is expected that lectins of a needed number of types appropriately corresponding the variation of sugar chains, if available, are highly useful as tools for analyzing various sugar chains. From a lectin library containing plural types of lectins or an arbitrary mass of lectins containing plural types of lectins, lectins needed for analyzing sugar chains are selected to thereby construct a lectin sub-library. Using the lectin sub-library thus constructed, cells having sugar chains are identified. Moreover, an indication method whereby cells can be conveniently identified is provided.