PURPOSE: To obtain a porous ceramics having good strength and capable of readily controlling porosity and pore diameter by casting a mixture of silicate slurry with aluminate slurry to prepare a porous hydrogel material, removing Na content and then burning the hydrogel material.

CONSTITUTION: Silicate slurry consisting essentially of sodium silicate, mullite powder, alumina powder and/or Al2O3 producing substance, a surfactant and metallic aluminum powder is mixed with aluminate slurry consisting essentially of sodium aluminate, mullite powder, alumina powder and/or Al2O3 producing substance and a surfactant. Then the mixture is cast and gellation and foaming are simultaneously carried out to afford a porous hydrogel material and sodium content is removed from the porous hydrogel material by leaching treatment and the hydrogel material is dried and burned at 1200-1700°C to provide the objective foaming type porous ceramics having about 50-1000μm pore diameter.