Method for manufacturing copolymer latex, and copolymer latex

The method for manufacturing a copolymer latex according to the present invention is a method for manufacturing copolymer latex obtained by emulsion polymerization, wherein the copolymer is composed of monomer components comprising 15-60 mass% of an aliphatic conjugated diene-based monomer, 5-35 mass% of an ethylene-based unsaturated carboxylic acid monomer, 0.5 to 30 mass% of a vinyl cyanide monomer, and 0-79.5 mass% of a monomer capable of copolymerization therewith, and emulsion polymerization is carried out by containing more than 0 mass% and 40 mass% or less of the entire amount of the ethylene-based unsaturated carboxylic acid monomer in the reaction system at the start of loading the polymerization initiator, starting the loading of the remainder of the ethylene-based unsaturated carboxylic acid monomer at or later than the time point of 5% of the time beginning from the arrival time at which the polymer conversion rate of the reaction system has arrived at 1.0% until the end time at which the loading of the entire amount of the monomer component has ended, and loading 92 mass% of the entire amount of the ethylene-based unsaturated carboxylic acid monomer before the time point of 80% of the time beginning from the arrival time until the end time.