Disclosed is a process for preparing a polyarylene sulfide, which involves polycondensing a dihalogenated aromatic compound with a source of sulfur in an organic polar solvent while dehydrating at pressure under which polycondensation is performed. This process avoids dehydration operation of the raw materials, particularly the source of sulfur, prior to polycondensation, thereby resulting in the production of the polyarylene sulfide having a high molecular weight.