Heat exchangers already known for use as evaporators for motor vehicle air conditioners have a heat exchanger body which comprises a plurality of vertical flat tubes arranged laterally at a predetermined spacing and each having a front and a rear fluid channel, and a front and a rear header interconnecting upper ends of the front fluid channels of all the flat tubes and upper ends of the rear fluid channels thereof respectively and each open at one end and closed at the other end, an end plate being disposed at each of lateral outer opposite sides of the heat exchanger body, the end plate at the open end side of the two headers having a fluid inlet hole in communication with the front header and a fluid outlet hole in communication with the rear header and being provided on an outer side of an upper edge portion of the plate with a pipe connecting member, the pipe connecting member having a fluid inlet passage communicating with the fluid inlet hole and a fluid outlet passage communicating with the fluid outlet hole. 
Efforts are made to reduce the front-to-rear width of evaporators for use in motor vehicle air conditioners.  It is required to reduce the front-to-rear width of not only the heat exchanger body but also of the pipe connecting member, while the problem to be overcome is to suppress the increase of pressure loss involved in the width reduction. 
An object of the present invention is to reduce the front-to-rear width of heat exchangers with the increase of pressure loss suppressed.,