A condensing combustion apparatus comprising: an upward combustion burner (20); a sensible-heat exchanger (40) which absorbs sensible combustion heat generated by the burner (20); and a latent-heat exchanger (50) which absorbs latent heat of steam included in a combustion gas which has passed the sensible-heat exchanger (40), wherein the sensible-heat exchanger (40) and the latent-heat exchanger (50) have the same lateral widths and are configured as fin-tube heat exchangers having common structures, and wherein a flow path through which the combustion gas, which has passed the sensible-heat exchanger (40), flows upward is formed on one side portion of the latent-heat exchanger (50), a flow path through which the combustion gas, which has passed the one side portion of the latent-heat exchanger (50), flows downward corresponding to a direction in which condensed water falls is formed on a middle portion of the latent-heat exchanger (50), and a flow path through which the combustion gas, which has passed the middle portion of the latent-heat exchanger (50), flows upward and discharges is formed on another side portion of the latent-heat exchanger (50).