To raise a rate of ozone decomposition which has not reached practical level by a conventional ozone decomposition catalyst, especially to raise a rate of ozone decomposition of high concentration ozone and to reduce ozone concentration after decomposition at or below an environmental standard value.

After a porous ceramic carrier is impregnated with an aqueous solution consisting essentially of nickel nitrate, heat treatment is performed at a temperature range between 400°C and 600°C to stick compounds consisting essentially of nickel oxide on a skeleton surface of the porous ceramic carrier. By using the obtained ozone decomposition filter, ozone concentration after decomposition is reduced at or below the environmental standard value. As the porous carrier, ceramics having three dimensional network structure or honeycomb structure can be used.