PURPOSE: To provide a high-strength flexible catalyst useful for cleaning automobile exhaustion gas by a method wherein machined steel powder is degreased and molded, sintered at a high temperature reducing atmosphere to form catalyst carrier, and immersed in aq. soln. of catalytically active metal or its cpd, for a very short period of time.

CONSTITUTION: Machined powder obtained as waste of by-product in machining process of steel products is treated for degreasing, molded in a desired shape, and sintered at a hihg-temperature reducing atmosphere. This provides sintered machined powder body consisting of pure reduced iron, which is then immersed in aq. soln. of catalytic active metal such as chloroplatinic acid or its cpd. for a very short period of time. This allows the soln. to be penetrated into the inside of the sintered body, the surface of each machined powder to be easily substituted by catalytic active metal, thereby providing a catalytic body having catalytically active metal surface layer. The catalyst body has great strength and flexibility, that is, a preferable property that withstands large pressure and abrasion.