To easily insert a heat exchanger when inserting the heat exchanger into an air conditioning unit by reducing friction by contacting a heat insulating material in a line with the line contact parts in the inserting direction of the heat exchanger in the installing part of the air conditioning case.

An evaporator 18 is installed in an air conditioning case 15 from an opening installing port, and a pair of heat exchanger holding parts 90, 91 are arranged in the evaporator installing part composed of the wall parts 95, 96 positioned downward over the diametrically expanded part 33 from the tongue part 34. The evaporator is composed of the arm parts 92 projecting to the evaporator 18 side from the respective wall parts 95, 96 and bending in the direction for running along them and the cross-sectional circular line contact parts 93 formed on the tips, and is extendedly formed in the inserting direction. Therefore, since the line contact parts 93 and a heat insulating material 60 covering the tank parts 67 of the evaporator 18 contact in a line with each other in the inserting direction, friction of both can be restrained to the minimum extent to easily insert the evaporator 18.