A method for producing polymer particles includes a preparation step for preparing a first oily liquid containing an oily olefin monomer, a radical polymerization initiator, and an iodine molecule; a synthesis step for obtaining a second oily liquid containing at least an iodine compound produced by a reaction between a radical generated by cleavage of the radical polymerization initiator and the iodine molecule in the first oily liquid; a suspension step for obtaining an oil droplet of the second oily liquid by suspending the second oily liquid in an aqueous solution containing an oxidizing agent, an acid, and a dispersant; and a polymerization step for polymerizing the oily olefin monomer in the oil droplet.