Exhaust gas-cleaning apparatus

An apparatus for cleaning an exhaust gas containing nitrogen oxide and particulate matter and discharged from a diesel engine, wherein said apparatus comprises a porous ceramic honeycomb filter and an SCR catalytic converter in this order from upstream, wherein said honeycomb filter has pluralities of flow paths partitioned by porous cell walls and a catalyst supported by said porous cell walls, with desired flow paths sealed by plugs, and wherein at least one plug on the side of an exhaust gas inlet is separate inward from an exhaust gas inlet end,

• wherein a ratio D/V of the diameter D (mm) of said honeycomb filter to the displacement V (liter) of said diesel engine is 15 mm/liter or more;
• said porous cell walls of said honeycomb filter have a thickness of 0.1-0.5 mm, a pitch of 1.2 mm or more, a porosity of 50-80% and an average pore diameter of 10-40 μm;
• and porous cell walls of a ceramic honeycomb structure for said SCR catalytic converter have a thickness of 0.05-0.25 mm, a pitch of 0.8-1.06 mm, a porosity of 25-45% and an average pore diameter of 1-10 μm.