PURPOSE: To obtain a silencer integral type gas heat exchanger of a high efficiency in which the acoustic pressure level is effectively lowered by installing a cylinder having a plurality of holes in a water chamber containing a fluid to be heated, driving an exhaust gas space into a plurality of parts by partitioning plates, penetrating a double tube consisting of a heat transfer tube at its inner side and an exhaust tube at its outer side, through the partioning plates, and further opening the exhaust gas tube into a different exhaust gas space.

CONSTITUTION: The cylinder 6 encircled by the water chamber 4 at its outer side and having a plurality of holes 5 in the water chamber 4, is installed, and a space surrounded by the water chamber 11 is used as an exhaust gas space 7. The exhaust gas space 7 is divided by a plurality of partioning plates. At the part which penetrates through the partioning plate 8, a double tube consisting of a heat transfer tube 14 at its inner side and an exhaust tube 15 at its outer side. The tip end of the exhaust tube 15 is opened to the different exhaust gas space.