Porous body data in which position information and type information are correlated is reference to take a curved surface solid including a parent virtual sphere and child virtual spheres as a virtual curved surface solid, and place multiple virtual curved surface solids so as to fill in space pixels with curved surface solid pixels occupied by virtual curved surface solids. Repeating this process, by placing multiple virtual curved surface solids within space in a porous body, the microstructure of the porous body is analyzed precisely. As for analysis, deriving of in-plane uniformity index γx, spatial uniformity index γ, pressure drop P, flow-through velocity T, and equivalent diameter d, for example, and acceptability determination based on derived values thereof, is performed.