PURPOSE: To obtain the titled fibers, having improved uniformity without pinholes, and useful for hemodialysis, etc., by extruding a cellulosic ester solution of specific substitution degree through the outer annular part of a spinneret of double pipe structure, wet spinning the solution, and saponifying the resultant fibers.

CONSTITUTION: A cellulosic ester having an acyl group substitution degree ≥2.7, e.g. cellulose acetate, is dissolved in a nonvolatile organic solvent, e.g. dimethylacetamide, to give a spinning solution, which is then extruded through the outer annular part of a spinneret having a double pipe structure while extruding a core solution, e.g. a mixed solution of ethanol-dimethylacetamide, simultaneously through the inner pipe part, and the extruded fibers are then led to a coagulating bath, e.g. an aqueous solution of dimethylformamide, and wet molded at 5°C or below to give hollow fibers. The resultant fibers are saponified and regenerated to afford the aimed regenerated hollow cellulosic fibers. A hemodialytic membrane of high safety without fear for dissolving out of toxic substances due to the absence of a swelling agent.