Three-way catalytic converter with reduced diameters on two ends of housing

The utility model relates to a three-way catalytic converter with reduced diameters on two ends of a housing, which comprises a housing, a carrier and a gasket. The both ends of the housing are gradually inwardly retracted to form ''reduced diameters'', and the both ends of the gasket are compressed into 1/3 of original thickness. The both ends of the housing are reduced in diameter and the both ends of the gasket are compressed into about 1/3 of original thickness, so that density and strength of end surface of the gasket are increased, and cross section area of end part is reduced; therefore, cutting effect of high speed rotary airstream formed by air discharging on the end surface of the gasket is reduced, and service life of the three-way catalytic converter is increased. Meanwhile, for the gasket is extruded, the gasket is more tightly connected with the carrier, thereby ensuring that the carrier will not be loosened and the gasket will not fall off after the catalytic converter has been used for a perio