To provide a catalyst converter having excellent durability, wherein generation of a crack on a catalyst supporting element is prevented even if repeatedly using the catalyst for a long period.

This catalyst converter is composed of the columnar catalyst supporting element made of ceramic and supporting a catalyst in an opening hole and/or a through hole for letting exhaust gas flow, a metallic shell cladding the outside of the catalyst supporting element, and a holding seal material disposed between the catalyst supporting element and the metallic shell and covering the periphery of the catalyst supporting element. A holding seal uncovering area in an exhaust gas inflow side of the catalyst supporting element is made to be not more than one-tenth of the length of the catalyst supporting element.