Disclosed is a heat exchanger for a condensing boiler supplying both heating water and hot water, which can use a double pipe as a sensible heat exchanger, instead of the use of an indirect heat exchanger. The heat exchanger includes: a sensible heat exchanger; and a latent heat exchanger made by connecting a plurality of unit heat exchangers to define exhaust gas pathway, each unit heat exchanger being manufactured in such a manner that three plates having a convexo-concave shape are stacked on one another to define a heating water pathway and a hot water pathway to be adjacent to each other in order to increase a heat transfer area.