PROBLEM TO BE SOLVED: To provide a leukocyte removal filter capable of filtering blood effectively using a whole filter surface without lowering a flow velocity in the thickness direction regardless of where the filter material is positioned in flow direction and width direction.SOLUTION: A leukocyte removal filter A is disclosed, wherein a height (t1) of an upstream-side passage forming rib 2A is 0.5 mm or more, the upstream-side passage forming rib provided on an inner face of an upstream-side container body 2 forming an upstream-side passage of a nonwoven or porous filter material the height (t2) of a downstream-side passage forming rib 3A is 0.5 mm or more, the downstream-side passage forming rib provided on an inner face of a downstream-side container body 3 forming a downstream-side passage of the filter material and (t1+t2) is from 1 mm and less than 5 mm.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2017,JPO&INPIT【課題】フィルター材の流れ方向及び幅方向の位置に関わらず厚み方向の流速が低下せずに、フィルター全面を有効に活用して血液を濾過できる白血球除去フィルターを提供する。【解決手段】不織布又は多孔質体のフィルター材の上流側の流路を形成する上流側容器本体2の内面に設けられた上流側流路形成用リブ2Aの高さ(t1)が0.5mm以上であり、フィルター材の下流側の流路を形成する下流側容器本体3の内面に設けられた下流側流路形成用リブ3Aの高さ(t2)が0.5mm以上であるとともに、(t1+t2)が1mm以上、5mm未満である白血球除去フィルターA。【選択図】図1
