US Patent 7919168 Plugged honeycomb structure

A plugged honeycomb structure includes: a honeycomb structure having porous partition walls separating and forming a plurality of cells communicating between an inlet end face on an inlet side of a fluid and an outlet end face on an outlet side of the fluid, and plugging portions for plugging an opening portion of each of predetermined cells on the inlet end face and an opening portion of each of the other cells on the outlet end face. There, 1.5% or more of the plugging portions plugging the opening portions of the predetermined cells on the inlet end face have a depressed pit on the end face on the inlet end face side.