Vehicle air-conditioning device with a multi-purpose heat exchanger

The refrigerant fluid circuit (3) comprises a compressor (13), a condenser (14) serving as a heat sink and a first evaporator (16) serving as a cold source. According to the invention, said circuit further comprises a second evaporator (20) and means (18) for circulating the fluid either only in the first evaporator or in both evaporators, depending on the required cooling capacity.