To provide a leucocyte removing filter material which has high leucocyte removability per unit volume, is good in the flow of a leucocyte-contg. liquid and incurs less damage on blood cells.

This leucocyte removing filter material is a filter material consisting of a porous element and a fibrous structure of ≥0.03 μm and <1.0 μm in the fiber diameter held at a porous element. The void volume of the filter material is ≥50% and <95%. The fibrous structural material of the leucocyte removing filter material is cellulose microfibrils within 1.0% in the degree of expansion of the fiber length by water. The filter material is capable of removing the leucocytes which are the cause for the side effect of transfusion with high efficiency from the leucocyte-contg. liquid and the high recovery rate of the useful blood components is obtainable. Further, the damage that the useful blood components receives is less and, therefore, the material is extremely useful as the filter material of the leucocyte removing filter material to be used at the time of the transfusion.