There is provided a novel production method of a chlorinated hyperbranched polymer that is optically stable and is capable of derivatizing the chlorinated hyperbranched polymer into various compounds. A production method of a chlorinated hyperbranched polymer for producing a chlorinated hyperbranched polymer of Formula (1): {where X is a chlorine atom; R1 is a hydrogen atom or a methyl group; and A1 is a phenylene-alkylene group, n is the number of repeating unit structures and is an integer of 2 to 100,000}, comprising the step of substituting a dithiocarbamate group of a hyperbranched polymer of Formula (3): (where R1, A1, and n are the same as defined in Formula (1); and each of R2 and R3 is a C1-5 alkyl group, a C1-5 hydroxyalkyl group, or a C7-12 arylalkyl group, or R2 and R3 optionally form a ring together with a nitrogen atom bonded to R2 and R3) with a chlorine atom using sulfuryl chloride.