A cell structure 10 having a plurality of cells 2 which are partitioned with partition walls 1 to form a honeycomb and which are flow paths of fluid, an outer wall 5 which encloses the cells 2 and a cavity 3 which pierces in the direction of a central axis P of the structure through a portion including the central axis P or a given axis parallel to the central axis P, where the cell structure further has an inner wall 4 on the inner surface of the cavity 3, a method for producing the cell structure, and a catalyst structure. The cell structure having the cavity has an excellent isostatic breaking strength and can exhibit proper sealing function in its cavities. Furthermore, a method for producing the cell structure, the catalyst structure, etc. are provided.