To prevent a telescoping phenomenon of a metal carrier for a catalytic device forming a roll-shaped honeycomb body of double-flat-plate structure.

A corrugated plate material 1 and two flat plate materials 2, 21 which are not joined with each other are piled up and are wound into a roll to form a first honeycomb body 11 for carrying a catalyst. A corrugated plate material 1 and a flat plate material 2 which are joined with each other are piled up and are wound into a roll to form a second honeycomb body 12 for carrying no catalyst. The second honeycomb body 12 is arranged downstream in the axial direction of the first honeycomb body 11 in series, and they are housed in an outer cylinder 15. The telescoping produced in the first honeycomb body 11 is retained by the end surface of the second honeycomb body 12 on the downstream side thereof. The honeycomb density of the second honeycomb body 12 is made smaller than that of the first honeycomb body 11. Since the second honeycomb body 12 does not carry a catalyst, heat by catalytic reaction is not produced therein to prevent a brazed part from being cracked by thermal stress.