A medical filter material characterized by comprising a dispersion of nanofibers of thermoplastic polymer having a number average diameter of 1 to 500 nm wherein the ratio of single fibers with a diameter of more than 500 nm and 1 μm or less is 3% or less in terms of weight ratio. Further, there are provided, utilizing the medical filter material, an extracorporeal circulation column and a blood filter. Through the employment of nanofibers small in fiber diameter dispersion, high in strength and high in productivity, there can be provided a medical filter material excellent in hemadsorption performance and protein adsorption performance. Through packing with this medical filter material, there can be provided high-performance extracorporeal circulation column and blood filter.