HEAT EXCHANGER AND WATER HEATER

PROBLEM TO BE SOLVED: To provide a heat exchanger and a water heater capable of sufficiently transmitting a heating value of combustion gas to a heat transfer tube and suppressing noise even in a dead angle region of the flow of the combustion gas in the heat transfer tube.SOLUTION: A fin 13 includes: cut-and-raised slits 13b; and cut-and-raised wall portions 13a. The cut-and-raised slits 13b are formed in regions RA adjacent in a first direction DA of at least one through-hole 13ca out of a plurality of through-holes 13ca, and include tunnel holes 13ba, 13bb, and 13bcextending in a second direction DB crossing the first direction DA. The cut-and-raised wall portions 13a are located in the second direction DB of the cut-and-raised slits 13b, protrude from a principal surface MS of the fin 13, and extend in the first direction DA.