An arrangement structure of heat exchangers in a condensing gas boiler is provided, which includes a casing provided with a
combustion chamber therein, and a
gas burner provided in the lower portion of the
combustion chamber. The arrangement structure of heat exchangers in a condensing gas boiler includes: a present
heat exchanger slantly arranged with a predetermined slope with respect to a
horizontal axis on a transverse cross-section in the casing; a
latent heat exchanger disposed in parallel with the present
heat exchanger, in the same area as that of the present
heat exchanger in the upper portion of the present heat exchanger; a condensed
waterspout provided in parallel with between the present heat exchanger and the
latent heat exchanger, whose one end contacts one of the inner wall surfaces of the casing and whose other end is disposed spaced from the other of the inner wall surfaces thereof; and an
exhaust gas flowing plate provided in parallel with the outer wall of the
latent heat exchanger, whose one end is spaced from one of the inner wall surfaces of the casing and whose other end contacts the other of the inner wall surfaces of the casing in order to induce
condensed water and
exhaust gas to flow in an identical direction. Thus, the
heat transfer area is maximized, and present heat and condensing conditions are made to improve a heat exchanging efficiency, and to accomplish compactness and
corrosion resistance of the boiler.