An exhaust gas purifying device includes: a columnar honeycomb carrier in which a plurality of cells which extend from an exhaust gas inflow side to an outflow side, and which serve as exhaust gas flow paths, are demarcated and formed by means of porous separating walls, a three-way catalyst supported in the honeycomb carrier, and a cylindrical case member in which the honeycomb carrier is housed, with the interposition of a retaining member. The honeycomb carrier includes outer circumferential plugging portions formed in such a way as to plug, to a prescribed depth, openings of cells in an outer circumferential portion of at least one end surface of the two end surfaces, in the central axis X-direction, of the honeycomb carrier, and inclined portions formed in a direction whereby the length, in the central axis X-direction, of the outer circumferential plugging portions decreases toward the outer circumferential edge.