flows therefrom onto the upwardly convex central portion 108 of the partition plate 106 by which the blood is divided into horizontally opposite areas in the frame 102 the blood as it flows downwardly is then directed vertically by the protrusions 122 and horizontally by the passages 123 as shown in fig6 the first filter elements 126a 126b are sufficiently pressed into the passages 123 and disposed in vertical gaps between the rows of the passages 123 therefore the blood necessarily penetrates the first filters 126a 126b and then enters the second filter elements 128a 128b therefore leukocyters are removed from the blood by the first filter elements 126a 126b and the second filter elements 128a 128b concentrated red cells which have passed through the second filter elements 128a 128b flows along the guides 131 on the lids 104a 104b into the space 112 from which the concentrated red cells are discharged via the filtrate outlet port 120 into the blood bag 64 fig3 a liquid filtering device according to still another embodiment of the present invention will be described with reference to fig7 and 8 those components of the liquid filtering device shown in fig7 and 8 which are identical to those of fig4 through 6 are denoted by identical reference numerals and will not be described in detail as shown in fig7 and 8 a pair of mesh screens 150 is disposed in the frame 102 at positions closest to the partition plate 106 more specifically the mesh screens 150 are positioned one on each side of the partition plate 106 and the first filter elements 126a 126b the second filter elements 128a 128b and the lids 104a 104b are successively disposed over the mesh screens 150 the mesh screens 150 allow.