To produce a PPS fiber for papermaking which has small heat-shrinkage and good separation property in water in production of undrawn PPS fiber for papermaking.

An undrawn polyphenylene sulfide staple fiber for papermaking is produced by producing an undrawn polyphenylene sulfide fiber by melt-spinning at a spinning velocity of 500-3,000 m/min, passing the undrawn fiber through a hot water bath at 70°C or more without drawing the fiber to effect heat-treatment for 0.5-10 sec, passing the heaet treated fiber through a dry-heat zone at 70-90°C in relaxed state to perform relaxation heat-treatment for 5-60 min, and cutting the resultant fiber to a predetermined length to obtain the staple fibers.