A heat exchanger includes plural heat transfer tubes and plural fins each having two opposing sides and plural opening ports on one side, of the two sides, for inserting and fastening the heat transfer tubes, and the heat exchanger is formed such that the plural heat transfer tubes and the plural fins cross each other, wherein at least two of the plural heat transfer tubes are fastened to the opening ports in a state of protruding from the one sides of the plural fins toward the outside of the plural fins.