To obtain a polyphenylenesulfide resin that has a reduced volatile content and is industrially useful, from a polyphenylenesulfide oligomer of 800-20,000 of a weight average molecular weight.

A mixture containing at least a polyhalogenated aromatic compound, a sulfiding agent and an organic polar solvent is heated to polymerize into a polyphenylene sulfide resin, then cooled to 220°C or below to obtain slurry (A) containing at least a granular polyphenylene sulfide resin, a polyphenylene sulfide oligomer, the organic polar solvent, water and a halogenated alkali metal salt. The polyphenylene sulfide oligomer of 800-20,000 weight-average molecular weight is obtained by removing at least the granular polyphenylene sulfide resin, the organic polar solvent, water and the halogenated alkali metal salt from the slurry (A). The polyphenylene sulfide resin is produced by thermal oxidation of the polyphenylene sulfide oligomer at 150-260°C under gas phase oxidizing atmosphere.