An automotive air conditioner comprises a housing having an air flow passage defined therein. The housing includes mutually opposed side walls between which a part of the air flow passage is defined. A fan is installed in an upstream part of the air flow passage to introduce air into the air flow passage. An evaporator is installed in the air flow passage at a position downstream of the fan. The evaporator is of a stack type including a plurality of flat tube elements which are stacked on one another. Every adjacent two of the flat tube elements leave therebetween a clearance which has inlet and outlet sides. The evaporator is postured in such a manner that the flat tube elements extend between the mutually opposed side walls of the housing having the inlet sides of the clearances of the flat tube elements directed upstream toward the fan.