The present invention provides a polysulfone type hollow fiber membrane which is reliable in safety and stability of performance and is easily incorporated into a module, and thus can be suitably used in a highly water permeable blood purifier for use in a therapy of chronic renal failure. The present invention relates to a polysulfone type selectively permeable hollow fiber membrane comprising a polysulfone type resin and a hydrophilic polymer as main components, and characterized in that (A) the content of the hydrophilic polymer in the uppermost layer of a surface of the polysulfone type hollow fiber membrane on the blood-contacting side is at least 1.1 times larger than the content of the hydrophilic polymer in the proximate layer of the surface on the blood-contacting side, and (B) the content of the hydrophilic polymer in the uppermost layer of the other surface of the polysulfone type hollow fiber membrane, i.e., the reverse side of the surface on the blood-contacting side, is at least 1.1 times larger than the content of the hydrophilic polymer in the uppermost layer of the surface on the blood-contacting side.
