To provide a heat exchange mechanism capable of improving heat efficiency and preventing uneven temperature distribution.

There are formed in a heat conductive sheet 6 a plurality of pipe grooves 7 in a straight manner in a length direction and disposed in parallel to heat exchange pipes 4 on a pipe mat P in the width direction. The heat exchange pipes 4 are fitted to the respective pipe grooves 7 in the heat conductive heat 6, and in the state where these heat exchange pipes 4 are covered a flat portion 8 of the heat conductive sheet 6 is brought into close contact with heat exchange surfaces.