[Problem] To obtain a hollow fiber membrane type blood purifier which has high blood compatibility and excellent antioxidation performance and is capable of retaining highly stable antioxidation performance even in a severe environment. [Solution] A hollow fiber membrane type blood purifier provided with a hollow fiber membrane, said hollow fiber membrane comprising a polysulfone-based resin, polyvinylpyrrolidone, a fat-soluble vitamin and an ester group-containing polymer, wherein: the content of the fat-soluble vitamin on the whole surface of the hollow fiber membrane is 2-18 mg inclusive per gram of the hollow fiber membrane； when the hollow fiber membrane is extracted with ethanol and, after drying the extract to solidness, the infrared absorption spectrum (IR) thereof is measured, the ratio of the absorbance [Abs(A)] at peak (A) around 1720-1730 cm-1 to the absorbance [Abs(B)] at peak (B) around 1660-1670 cm-1 [Abs(A)/Abs(B)] is 0.01-0.3 inclusive； and the moisture content of the hollow fiber membrane is 0-600 mass% inclusive.
