To prevent coolant backflow from a pulsation suppression means to an electric compressor when the compressor stops, while setting the pulsation suppression means in a position higher than the electric compressor. A heat-pump-type air-conditioning device comprises a coolant discharge pipe (31), (32) linking an electric compressor (10) disposed in a motor compartment (M) of an electric vehicle (1) and a condenser (25) disposed in a passenger compartment (R), and channeling coolant from the electric compressor (10) to the condenser (25). In this heat-pump-type air-conditioning device, a muffler (11) for suppressing pulsation in the coolant discharged from the electric compressor (10) is provided at a position partway along the coolant discharge pipe (31), (32), and the muffler (11) is disposed in a position higher up in the vehicle than the than a coolant discharge port (10b) of the electric compressor (10). A coolant inflow port (11a) of the muffler (11) is set at a position higher up in the vehicle than the than a coolant outflow port (11b) of the muffler (11).