The combustion of particulates that have accumulated on a catalyst layer (7) proceeds with good efficiency, in both a rapid combustion region and a slow combustion region. A material of Rh-doped Ce-containing composite oxide particles supporting Pt and a material of composite particles supporting Pt are both present on the catalyst layer (7) of the exhaust gas flow path walls of a filter (1). The composite particles are formed by mixing and aggregating Ce-free and Zr-containing composite oxide particles and activated alumina particles.