In this study, direct contact melting of porous material as the PCM is investigated experimentally and analytically. The PCM is made of fine ice particles, the particle diameter of which is changed as an experimental parameter. In the experiment, cylindrical porous materials are melted on the heating plate, and the time dependency of the height of the PCM and the temperature of the heating surface are measured. In the analysis, the melting process that the melted liquid permeates into the solid is calculated as a direct contact melting phenomenon. As the result, it was found that the melting rate increases in the initial stage of the melting process, because the melted liquid permeates into the solid rapidly due to capillary effect and the liquid film becomes thinner. The phenomenon was found to be more significant for smaller particle size. Moreover, the experimental and analytical results coincide with each other in case of the small particle.