Poly(p-phenylene sulfide)(PPS) films with different degrees of crystallinity were prepared by changing annealing or drawing conditions. PPS films were attached to a four-in-line probe apparatus that made it possible to monitor conductivity during doping. Sulfur trioxide doping of PPS increased an electrical conductivity as high as 10-4 S/cm within 30 min. of doping time at room temperature. In SO3 doping the electrical conductivity of PPS film proved to be particularly sensitive to the degree of orientation and the degree of crystallinity of starting polymer. The conductivity of film annealed at 24$0^{circ}C$ for 30 min. was twenty times higher than that of unannealed film. Although PPS films had the same degree of crystallinity, the conductivity of drawn PPS film was higher than that of undrawn PPS film after doping. By SO3 doping, the disappearance of crystalline region in PPS was confirmed from the result of X-ray diffractogram.