PURPOSE: To obtain the subject polymer, comprising a specific structural unit, having excellent antimicrobial, anthelmintic, antioxidizing and deodorizing actions and useful as a food, a coating, a fiber, etc. CONSTITUTION: This acrylamidomethylpolyphenol polymer comprises (A) 10-100 mol % structural unit of formula I [R<1> is H or CH3; R<2> is a group of formula II (R<3> is H or OH; R<4> is H or 3,4,5-trihydroxybenzoyl; one of a1 to a4 is a single bond and other three are H) or a group of a benzene skeleton, a naphthalene skeleton or an anthracene skeleton all having >=2 OH groups] and (B) 0-90 mol % structural unit of formula III (R<5> is R<1>; R<6> is H or an alkyl) or a structural unit of the formula [CH2-C(R<7>R<8>)][R<7> is R<1>; R<8> is H, Cl, CN, etc.]. Furthermore, the method for producing the polymer is to carry out the condensing reaction of, e.g. an acrylamide copolymer comprising the structural unit of formula III and the structural unit of the formula [CH2-C(R<7>R<8>)] with the corresponding polyphenol such as a compound of formula IV in the presence of an acidic catalyst in a reaction medium.