To provide a method for producing a block copolymer, capable of obtaining the block copolymer in a high yield.

This method for producing the block copolymer comprises reacting a macromonomer composition with a vinyl monomer for block copolymerization. The macromonomer composition is obtained by polymerizing a vinyl monomer mixture for producing the macromonomer at 160-350°C, wherein the vinyl monomer mixture contains a vinyl monomer having an alkyl group at the α-position in an amount of 40-80 wt.% based on the total amount of monomers supplied for producing the macromonomer composition. The vinyl monomer for the block copolymerization contains the vinyl monomer having the alkyl group at the α-position in an amount of 65-100 wt.% based on the total amount of the macromonomer composition and the vinyl monomer supplied for the block copolymerization.