To provide a heat pump device for a vehicle, an air conditioning system for a vehicle and a noise suppression method which maintain air conditioning performance while suppressing noise of an electric compressor.

A heat pump device for a vehicle is the heat pump device for a vehicle which performs heat exchange between a cooling liquid and a cooling medium and performs air conditioning of a vehicle by the cooling liquid, and it includes: an electric compressor having an electric motor and compressing and discharging the sucked cooling medium; a water pump for transporting the cooling liquid; and a control unit for controlling the drive of the electric motor and the water pump. The control unit is configured in such a manner that, when acquiring a silent operation request signal for requesting noise reduction, it suppresses rotation frequency of the electric motor and maintains or raises the rotation frequency of the water pump.