To provide a method for efficiently producing in a short time a vinyl acetal resin of high acetalization degree in a granular form of excellent handleability.

The method for producing a vinyl acetal resin comprises: a reaction step of obtaining a reaction liquid with a vinyl acetal resin dispersed highly therein by subjecting a mixed liquid of an aldehyde and a vinyl alcohol-based resin or vinyl acetate-based resin solution to an acetalization reaction in a high-temperature and high-pressure fluid of 100-400°C and 0.5-100 MPa; and a granulation step of obtaining the objective granular vinyl acetal resin by charging the reaction liquid, via small holes, into water at a temperature lower than the glass transition temperature of the vinyl acetal resin obtained by the preceding step.