Provided is a method and an apparatus for producing a polyvinyl alcohol that can reduce energy consumption without deterioration in quality of the product polyvinyl alcohol. First, one or more vinyl esters are polymerized or a vinyl ester and other copolymerizable monomers are copolymerized to give a polyvinyl ester. Then, a raw saponification solution containing the polyvinyl ester and an organic solvent is fed through a channel 1 and a saponification catalyst-containing solution is introduced into the center of the channel. They are then mixed with static mixers 2 and the mixture 4 is subjected to saponification reaction, as it is placed on a belt 3.