Abstract: A catalyst for decomposing ozone comprising a carrier and a catalytic active substance having ozone resolvability carried thereon in a thickness of 10 to 200 .mu.m. Consequently, ozone can efficiently be removed. The invention also includes the catalytic active substance or ozone adsorption substance which is contained in the carrier, such that the combination of the carrier and its contained material has ozone resolvability or ozone adsorbing ability in itself. Accordingly, the combination of these two features allows the thickness of the catalytic active substance carried on a carrier surface to be reduced to the range from 5 to 100 .mu.m. Thus, improved productivity, durability of the catalyst and ozone removing efficiency are provided.