To provide a method for stably manufacturing an ethylene-vinyl acetate copolymer (EVA) for a long time without continuously supplying the raw materials.

The method for manufacturing EVA in a polymerization solution in a vessel is provided, which solution includes ethylene, vinyl acetate, methanol and a polymerization initiator. The method comprises performing a step for cooling a gas including vapor evaporated from the polymerization solution to generate condensate of at least a part of the gas and a step for introducing the condensate to the polymerization solution to evaporate at least one ingredient of the condensate so as to be included in the above-mentioned vapor the above-mentioned at least one ingredient.