Abstract: Here is disclosed a vehicle-loaded heat exchanger comprising a plurality of tubes extending in parallel with one another, an inlet header pipe and an outlet header pipe respectively connected to opposite ends of said tubes, wherein each of the header pipes is longitudinally divided into two components, namely, a tank and an end plate both presenting outwardly swelling walls and the end plate is integrally joined to the tank with opposite joint side edges of the former bearing against the inner surfaces of corresponding opposite joint side edges of the latter. With such heat exchanger, parallel flows of coolant passing through a plurality of tubes are established between the inlet and outlet header pipes and thereby desired heat exchange is obtained.