Three kinds of beads with different mean diameters were each packed in a rectangular cell. These packed beads were saturated with NaCl-aqueous solution and used as porous media. The solidification process of the porous medium from one of the vertical walls was studied experimentally and analytically. In the analysis, the permeability in the mushy region was expressed as the nth power function of the volume fraction of the liquid phase in the mushy region. As the results, the influences of the initial concentration of the solution and the mean diameter of beads on the solidification process were clarified.