An air conditioner for a vehicle has a housing. The housing defines an air passage therein, includes a suction port, and houses a blower fan. The blower fan draws an air from the suction port and discharges the air into the air passage. The housing includes a facing portion that faces an inlet defining member including an air inlet. The facing portion includes the suction port. The facing portion has a rib that protrudes from the facing portion toward the inlet defining member. The facing portion and the rib define at least a part of an air guiding passage that guides the air from the air inlet to the suction port.