A (meth)acrylic copolymer comprising: at least one kind of constitutional unit selected from the group consisting of a constitutional unit (A1) having at least one kind of structure (I) selected from the group consisting of structures represented by the following formula , formula , or formula ; and a constitutional unit (B) derived from a macromonomer (b), wherein macromonomer (b) has a radically polymerizable group and two or more constitutional units represented by the following formula (b'): (where, X represents -O-, -S-, or -NR 14 -, R 14 represents a hydrogen atom or an alkyl group, R 1 and R 2 each represent a hydrogen atom or an alkyl group having from 1 to 10 carbon atoms, R 3 and R 5 each represent an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group, or an aryl group, and R 4 and R 6 each represent an alkylene group having from 1 to 10 carbon atoms); (where, R 41 represents a hydrogen atom, a methyl group, or CH 2 OH and R 42 represents OR 43 , a halogen atom, COR 44 , COOR 45 , CN, CONR 46 R 47 , or R 48 , where R 43 to R 47 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted nonaromatic heterocyclic group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, or an unsubstituted or substituted organosilyl group and R 48 represents an unsubstituted or substituted aryl group or an unsubstituted or substituted heteroaryl group). at least one kind of constitutional unit selected from the group consisting of a constitutional unit (A1) having at least one kind of structure (I) selected from the group consisting of structures represented by the following formula , formula , or formula ; and a constitutional unit (B) derived from a macromonomer (b), wherein macromonomer (b) has a radically polymerizable group and two or more constitutional units represented by the following formula (b'): (where, X represents -O-, -S-, or -NR 14 -, R 14 represents a hydrogen atom or an alkyl group, R 1 and R 2 each represent a hydrogen atom or an alkyl group having from 1 to 10 carbon atoms, R 3 and R 5 each represent an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group, or an aryl group, and R 4 and R 6 each represent an alkylene group having from 1 to 10 carbon atoms); (where, R 41 represents a hydrogen atom, a methyl group, or CH 2 OH and R 42 represents OR 43 , a halogen atom, COR 44 , COOR 45 , CN, CONR 46 R 47 , or R 48 , where R 43 to R 47 each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted nonaromatic heterocyclic group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, or an unsubstituted or substituted organosilyl group and R 48 represents an unsubstituted or substituted aryl group or an unsubstituted or substituted heteroaryl group). <EOS>