An electric heating device for an exhaust gas catalyst, the electric heating device including a sleeve and a heating cellular structure which is heated by a flow of electric current and which is contained in the sleeve. The electric heating device being designed to be positioned in a segment of an exhaust gas pipe upstream of a catalyst, so as to completely occupy a cross section of the segment such that exhaust gases flowing in the pipe pass through the cellular matrix before reaching the catalyst. The heating cellular structure is designed to dissipate an inhomogeneous thermal power in a section perpendicular to the direction of flow of the exhaust gases, such that the temperature of the exhaust gases at the outlet of the heating cellular structure is homogeneous in a section perpendicular to the direction of flow of the exhaust gases.