The present invention provides a substrate for ligand support in which a copolymer represented by the following formula (1) is bonded to at least a surface of a water-insoluble carrier:[in the formula (1), n and m represent a positive integer, and a value of m / (n + m) is greater than or equal to 0.1 and less than or equal to 0.45, R1 represents H or CH3, R2 represents an organic group including an electrophilic functional group, and R3 represents
