Block copolymer

A block copolymer comprising:

• a polystyrene block comprising a styrene unit;
• and
• a polyalkyl (meth)acrylate block comprising an alkyl (meth)acrylate unit,
• the block copolymer comprising an organic group that is bound to at least one end of a main chain of the block copolymer and that comprises a hetero atom,
• wherein a polymerization initiation end of the block copolymer comprises a structure derived from an alkyl lithium,
• wherein the organic group included in the block copolymer comprises a nitrogen atom, a sulfur atom, a phosphorus atom, a tin atom, or a combination thereof, or is represented by formula (1):
• wherein, in the formula (1), R1 represents a single bond or a divalent organic group having 1 to 30 carbon atoms;
• and R2 represents a hydrogen atom, an aliphatic linear hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, or a group in which the aliphatic linear hydrocarbon group having 1 to 30 carbon atoms or the alicyclic hydrocarbon group having 3 to 30 carbon atoms comprises a hetero atom between adjacent two carbon atoms, and
• wherein the organic group is not a monomeric unit included in the block copolymer.