The purpose of the present invention is to provide a novel vinyl monomer having a diglycolamidic-acid-type ligand useful in the production of an adsorbent separation material for separating and recovering rare earth elements. The vinyl monomer of the present invention has a diglycolamidic-acid-type ligand represented by general formula (1). (In formula (1), R1 represents a hydrogen atom or a C1-3 alkyl group; when R1 is a hydrogen atom, X is a single bond or a C2-7 optionally substituted divalent organic group; when R1 is a C1-3 alkyl group, X is a single bond or a C1-7 optionally substituted divalent organic group. n is 0 or 1; when n is 0, R2 is a hydrogen atom, a C1-3 alkyl group, or a C1-2 acyl group or aldehyde group; when n is 1, R2 is a C1-3 alkylene group.)