In the Kanto area, the regulation of diesel engine exhaust gas control was began from October, 2004. Because ceramic honeycomb catalysts in generally used had the filter structure, a lot of problems were caused by the particulate matter(PM) accumulation. Applying the Micro-fin to the diesel vehicles exhaust gas cleanup system, amount of PM removed in 61.5% from results of the 13 mode running test. By impregnation Pt nano-particles on the Micro-fin^<TM>, a remarkable effects was also appeared in the PM combustion in low temperature range, in addition to CO and total HC conversion.