PURPOSE: To provide a heat exchanger in which the withstanding pressure of a tank is secured at low costs without increasing the wall thickness of the tank.

CONSTITUTION: Heat exchange pipes 27b are passed through a bottom wall 23b from which the heat exchanger pipes are inserted into a tank 23, are made to get in contact with a top wall 23a and are secured to the top wall 23a and the bottom wall 23b by brazing 41. The heat exchanger pipes are respectively provided with refrigerant passages 45 in the portions of the pipes-inserted into the tank 23. Thus, the smooth flow of refrigerant is realized between the interior of the tank 23 and the heat exchanger pipes 27b so that the withstanding pressure is sufficiently secured in respect of the refrigerant pressure within the tank 23.