A vehicular rotating electrical machine apparatus comprising: a rotating electrical machine including a shaft rotatably supported by a pair of brackets (18,19) each having a suction hole (18a,19a) at an end face and an exhaust hole (18b,19b) at an outer radial periphery, a rotor disposed in the pair of brackets (18,19), fixed to the shaft, having a field winding mounted to an inside, and having cooling fans mounted to both end faces, and an armature fixed to the pair of brackets (18,19) at an outer periphery of the rotor to surround the rotor and including an armature iron core on which an armature winding is wound, and an inverter unit which is configured to convert DC power of a battery into AC power, supply the AC power to the armature winding and cause the rotor to generate rotating power, or to convert AC power generated in the armature winding into DC power and to charge the battery, in which the inverter unit has a substantially hollow cylindrical shape or hollow polygonal prism shape, and includes a heat sink (401, 402, 403) having many heat radiating fins (410a, 410b) extending from at least part of an outer surface, and the inverter unit surrounds the shaft at an anti-load side end of the rotating electrical machine, characterized in that the many heat radiating fins (410a,410b) are made of a metal material and extend from a rear bracket side end face and an outer radial peripheral surface of the heat sink, the inverter unit is integrally fixed to an outside end face of the rear bracket and is covered by a cover that is mounted so as to surround the inverter unit and a brush holder and provided with many suction holes at an outer radial peripheral surface, and the inverter unit is disposed to cause the cooling air sucked by the cooling fan through the suction holes of the outer radial peripheral surface of the cover to flow along the outer radial peripheral surface side heat radiating fins and the rear bracket side heat radiating fins to a suction hole provided in the rear bracket, to be bent in the centrifugal direction by the cooling fan and to be exhausted from the exhaust hole, thereby cooling the heat radiating fins (410a, 410b) before cooling of the rotating electrical machine, wherein a partition wall or an air-guide wall to control an exhaust direction is provided to the cover or the bracket to which the inverter unit is fixed, so that high temperature exhaust cooling air exhausted from the exhaust hole provided in the outer radial periphery of the bracket is not circulated to and sucked through the suction holes of the cover. a rotating electrical machine including a shaft rotatably supported by a pair of brackets (18,19) each having a suction hole (18a,19a) at an end face and an exhaust hole (18b,19b) at an outer radial periphery, a rotor disposed in the pair of brackets (18,19), fixed to the shaft, having a field winding mounted to an inside, and having cooling fans mounted to both end faces, and an armature fixed to the pair of brackets (18,19) at an outer periphery of the rotor to surround the rotor and including an armature iron core on which an armature winding is wound, and a shaft rotatably supported by a pair of brackets (18,19) each having a suction hole (18a,19a) at an end face and an exhaust hole (18b,19b) at an outer radial periphery, a rotor disposed in the pair of brackets (18,19), fixed to the shaft, having a field winding mounted to an inside, and having cooling fans mounted to both end faces, and an armature fixed to the pair of brackets (18,19) at an outer periphery of the rotor to surround the rotor and including an armature iron core on which an armature winding is wound, and an inverter unit which is configured to convert DC power of a battery into AC power, supply the AC power to the armature winding and cause the rotor to generate rotating power, or to convert AC power generated in the armature winding into DC power and to charge the battery, in which the inverter unit has a substantially hollow cylindrical shape or hollow polygonal prism shape, and includes a heat sink (401, 402, 403) having many heat radiating fins (410a, 410b) extending from at least part of an outer surface, and the inverter unit surrounds the shaft at an anti-load side end of the rotating electrical machine, characterized in that the many heat radiating fins (410a,410b) are made of a metal material and extend from a rear bracket side end face and an outer radial peripheral surface of the heat sink, the inverter unit is integrally fixed to an outside end face of the rear bracket and is covered by a cover that is mounted so as to surround the inverter unit and a brush holder and provided with many suction holes at an outer radial peripheral surface, and the inverter unit is disposed to cause the cooling air sucked by the cooling fan through the suction holes of the outer radial peripheral surface of the cover to flow along the outer radial peripheral surface side heat radiating fins and the rear bracket side heat radiating fins to a suction hole provided in the rear bracket, to be bent in the centrifugal direction by the cooling fan and to be exhausted from the exhaust hole, thereby cooling the heat radiating fins (410a, 410b) before cooling of the rotating electrical machine, wherein a partition wall or an air-guide wall to control an exhaust direction is provided to the cover or the bracket to which the inverter unit is fixed, so that high temperature exhaust cooling air exhausted from the exhaust hole provided in the outer radial periphery of the bracket is not circulated to and sucked through the suction holes of the cover.