A rotating electric machine system includes: a rotating electric machine including a stator and a rotor arranged with a gap to the stator; a casing configured to hold the stator; an electric power conversion apparatus held by the casing, and configured to drive the rotating electric machine; and a first cooling flow path arranged in a portion of the casing between the stator and the electric power conversion apparatus, via which cooling medium is caused to flow so as to cool the stator and the electric power conversion apparatus. And; the electric power conversion apparatus comprises a power module configured to include a power semiconductor element therein; the power module comprises a heat radiation fin; and the heat radiation fin is arranged to protrude toward a cooling medium side via an opening formed between the power module and the first cooling flow path.