A process for producing polyacrylonitrile-base precursor fibers for production of carbon fibers, which comprises spinning a spinning dope containing 10 to 25 wt % of a polyacrylonitrile-base polymer having an intrinsic viscosity of 2.0 to 10.0 by extruding the spinning dope from a spinneret by a wet spinning or a dry wet spinning method, drying and heat-treating fibers obtained by the spinning, and then steam drawing the resulting fibers, wherein the linear extrusion rate of the polyacrylonitrile-base polymer from the spinneret is 2 to 15 m/min.