PURPOSE: To improve a warming up property without reducing the catalyst support quantity of a monolithic catalyst during an engine cold period after starting an engine, etc., in the monolithic catalyst to clean exhaust gas from the internal combustion engine of an automobile, etc.

CONSTITUTION: Heat capacity per unit volume of the exhaust gas inflow part of a catalyst support 3 is set smaller than the heat capacity per the unit volume of an exhaust gas outflow part in a monolithic catalyst consisting of the catalyst support 3, a coating material 5 to be approximately uniformly applied on the surface of the catalyst support 3, and a catalyst component 6 to be carried by the coating material 5.