Block copolymer, method of producing block copolymer, and method of producing structure containing phase-separated structure

A block copolymer containing a first block consisting of structural units represented by general formula (1-1) shown below:

• wherein R represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms;
• Ys01 represents a divalent linking group;
• Rs01a represents an organic group having a polar group selected from the group consisting of formulae (Rs01-1) to (Rs01-11) shown below:
• wherein Rs001 represents an organic group;
• and,
• and a second block selected from the group consisting of:
• a block in which structural units derived from styrene or a styrene derivative are repeatedly bonded,
• a block in which structural units derived from an acrylate ester which may have the hydrogen atom bonded to the carbon atom on the α-position substituted with a substituent are repeatedly bonded,
• a block in which structural units derived from acrylic acid which may have the hydrogen atom bonded to the carbon atom on the α-position substituted with a substituent are repeatedly bonded,
• a block in which structural units derived from an alkyleneoxide are repeatedly bonded, and
• a block in which silsesquioxane structure-containing structural units are repeatedly bonded.