To grind a partition wall forming material layer by a grinding method causing no environmental pollution, and capable of reducing a cost, because of fearing a problem of the environmental pollution for conventionally using an inorganic particulate material such as SiC and SiO2 as an abrasive when grinding the partition wall forming material layer formed on a base board in a prescribed pattern.

When grinding the partition wall forming material layer formed on the base board in the prescribed pattern, the partition wall forming material layer is ground by using an ice grain and a dry ice grain as the abrasive.