A heating apparatus for a vehicle includes a heat exchanger for implementing heat exchange between coolant which has cooled an engine and air directed to a vehicle interior to heat the vehicle interior. A viscous heater has a rotor and a heating chamber containing viscous fluid. The rotor rotates when being subjected to rotational power of the engine. The viscous fluid is subjected to a shear force and is heated when the rotor is subjected to the rotational power. The viscous heater heats the coolant fed to the heat exchanger as the viscous fluid in the heating chamber is heated. A clutch is operative for selectively permitting and inhibiting transmission of the rotational power from the engine to the rotor. A belt transmission device connects the engine and the clutch. A physical quantity detecting device is operative for detecting a physical quantity related to a rotational speed of the rotor. A control device is operative for controlling the clutch to inhibit the transmission of the rotational power from the engine to the rotor when the physical quantity detected by the physical quantity detecting device is equal to or less than a predetermined value.