Abstract: A heat recovery unit in which cooling water absorbs heat generated in a water-cooled alternator and a viscous heater in which cooling water absorbs heat generated in a viscous fluid within a heat-generating chamber have a common cooling water passage. Further, a rotor of the alternator and a rotor of a viscous heater are disposed on a shaft to have a common driving shaft and a common V-belt. Therefore, cooling water pipes of a cooling water circuit are simply connected, a large space is not necessary for winding the V-belt of a belt transmitting mechanism, and the number of parts of a heating apparatus can be decreased. Further, because heat generated in the viscous fluid of the viscous heater and heat generated with an operation of the alternator are used as a supplementary heating source, a sufficient heating capacity can be provided for a passenger compartment even in a vehicle in which heat generated in the engine is small.