There is disclosed a plugged honeycomb structure. A plugged honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls defining a plurality of cells which become through channels for a fluid and extend from a first end face to a second end face, and plugging portions disposed in open ends of predetermined cells in the first end face and open ends of residual cells in the second end face, and the partition walls are constituted of a porous body including α-Al2O3 as a main phase and further including cordierite and Y2Si2O7.