PURPOSE: To disturb airflow around pipes in first row and increase the heat conducting area of the heat exchanger also to improve the heat conducting performance of the heat exchanger by permitting heat source fluid to flow through the inside of cylindrical tubular bodies.

CONSTITUTION: The cylindrical members 5, having cylindrical outer peripheral surfaces and arranged in parallel along the side rim of upstream side of plate fins 1 with intervals into directions intersecting with the flow direction of the airflow, are provided and both ends thereof are penetrated through and fixed to the end plates 3. The cylindrical tubular bodies 5 are connected to the same bodies 5 mutually and are connected to the pipes 2 so as to flow the heat source fluid through the inside of the cylindrical tubular bodies 5. The cylindrical tubular bodies 5 are arranged in zigzag with respect to the pipes 2a in the first row. When air is flowed into the direction A, the airflow is disturbed in the wake flow of the cylindrical tubular bodies 5 by the same bodies 5 and eddy currents X are generated. As a result, the airflow around the pipes 2a in the first row is disturbed and heat conducting performance around the pipes 2 is improved remarkably. Further, the cylindrical tubular bodies 5 are connected to the pipes 2 and the heat source fluid flows through the inside of them, therefore, heat exchange may be effected in the cylindrical tubular bodies 5 with air, therefore, the heat conducting area is increased resultantly, the amount of heat exchange is increased and the heat conducting performance as the heat exchanger may be improved remarkably as the whole thereof.