An air conditioning system that is to be incorporated in a motor vehicle including at least a passenger compartment for a passenger and a motor room that accommodates a secondary cell or a fuel cell for driving wheels with a motor, for conditioning air in the passenger compartment, the air conditioning system comprising at least: at least one catalyst heater including a catalyst and a fuel tank that supplies a fuel to the catalyst; an air conditioning duct; and an air conditioning fan, wherein the at least one catalyst heater generates heat by supplying the fuel in the fuel tank and an oxidizing gas to the catalyst, the air conditioning duct is connected with an intake port for drawing air from the passenger compartment and a blowing port for blowing air into the passenger compartment, the intake port and the blowing port being formed in the passenger compartment, the air conditioning fan is provided in the air conditioning duct, the air in the passenger compartment is drawn into the air conditioning duct through the intake port, and the drawn air flows through the air conditioning duct and is blown from the blowing port with the air conditioning fan so that the air in the passenger compartment is capable of circulating, characterized in that: the air drawn into the air conditioning duct is conditioned by utilization the heat generated with the at least one catalyst heater, and the conditioned air is blown into the passenger compartment so that the air in the passenger compartment is conditioned, the air conditioning system further includes a function of cooling the interior of the passenger compartment by utilization of a refrigerant, wherein the air drawn into the air conditioning duct is cooled by a heat pump method by utilization of the refrigerant heated with the catalyst heater, and the cooled air is blown into the passenger compartment so that the interior of the passenger compartment is cooled, the catalyst heater further includes a heat conductor connected with the catalyst, the heat conductor of the catalyst heater is inserted into the air conditioning duct, the air drawn into the air conditioning duct is heated by utilization of the heat generated with the catalyst heater through the heat conductor and the heated air is blown into the passenger compartment so that the interior of the passenger compartment is heated. at least one catalyst heater including a catalyst and a fuel tank that supplies a fuel to the catalyst; an air conditioning duct; and an air conditioning fan, wherein the at least one catalyst heater generates heat by supplying the fuel in the fuel tank and an oxidizing gas to the catalyst, the air conditioning duct is connected with an intake port for drawing air from the passenger compartment and a blowing port for blowing air into the passenger compartment, the intake port and the blowing port being formed in the passenger compartment, the air conditioning fan is provided in the air conditioning duct, the air in the passenger compartment is drawn into the air conditioning duct through the intake port, and the drawn air flows through the air conditioning duct and is blown from the blowing port with the air conditioning fan so that the air in the passenger compartment is capable of circulating, the air drawn into the air conditioning duct is conditioned by utilization the heat generated with the at least one catalyst heater, and the conditioned air is blown into the passenger compartment so that the air in the passenger compartment is conditioned, the air conditioning system further includes a function of cooling the interior of the passenger compartment by utilization of a refrigerant, wherein the air drawn into the air conditioning duct is cooled by a heat pump method by utilization of the refrigerant heated with the catalyst heater, and the cooled air is blown into the passenger compartment so that the interior of the passenger compartment is cooled, the catalyst heater further includes a heat conductor connected with the catalyst, the heat conductor of the catalyst heater is inserted into the air conditioning duct, the air drawn into the air conditioning duct is heated by utilization of the heat generated with the catalyst heater through the heat conductor and the heated air is blown into the passenger compartment so that the interior of the passenger compartment is heated.