Abstract: The present invention relates to an amphoteric resin obtained by condensation of polyethylenepolyamine and butane-1,2,3,4-tetra-carboxylic acid. The present invention can provide several forms of amphoteric resins such as linear structure, somewhat cross-linked water insoluble and water swellable structure and water insoluble and cross-linked structure, since the resin contains in its repeating units an imino group, a carboxylic radical and an amido group. The resin can form a chelate with several kinds of metal ions. Furthermore, the resin can also be modified by introducing several kinds of functional groups to bestow upon the resin particular chelating ability. Therefore the invention can provide novel resins, which have a strong chelating faculty and are suitably used for removing and recovering agents of heavy metals and noble metals.