Patent attributes
A honeycomb filter including: a honeycomb structure having a porous partition wall provided surrounding a plurality of cells; and a plugging portion disposed to seal either one end portion on the inflow or the outflow end face side of the cells, wherein the cell in which the plugging portion is provided at the outflow end face side and the inflow end face side is open is defined as an inflow cell, the cell the plugging portion is provided at the inflow end face side and the outflow end face side is open is defined as an outflow cell, the honeycomb structure further has a trapping layer for the particulate matter on an inner surface side of the partition wall, the trapping layer includes a portion composed of a sintered body of CeO2 particles on at least a surface layer, and the average particle diameter is 1.1 μm or less.