PURPOSE: To obtain the titled synthetic fibers having improved processability at a low cost, by mixing a solution of an acrylic polymer with a solution of an electrically conductive polymer, spinning the resultant mixture solution into a coagulation bath, washing the resultant fibers with water, drying the washed fibers, and shrinking the dried fibes under wet heat conditions.

CONSTITUTION: (A) A solution of an acrylic polymer containing preferably ≥80wt% acrylonitrile is mixed with (B) a solution of an electrically conductive polymer consisting of (i) 10W50wt% electrically conductive fine particles, preferably carbon black or metal (oxide), and (ii) 90W50wt% elastic polymer, e.g. polyurethane, miscible but incompatible with the acrylic polymer at (50/50)W (90/10) weight ratio, and the resultant mixture solution is then spun into a coagulation bath at 0.2W2.0 spinning draft. The resultant fibers are then washed with water, dried and shrunk under wet heat conditions to give the aimed synthetic fibers having a structure in which the component (B) is dispersed in the form of discontinuous slender islands in the fiber axis direction.