Patent attributes
Provided is an exhaust gas purification device that ensures an improved purification performance and a suppressed pressure loss. An exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. disposed on a surface on the inflow cell side in an inflow side region of the partition wall. When a gas permeability coefficient of an inflow side partition wall portion including the inflow side region of the partition wall and the inflow cell side catalyst layer is Ka and a gas permeability coefficient of an outflow side partition wall portion including an outflow side region at least from the predetermined position to an outflow side end of the partition wall is Kb, a ratio Ka/Kb of the gas permeability coefficients is within a range of 0.4 or more and 0.8 or less.