A cooling structure of a rotary electric machine for power generation which includes a rotor and a stator includes a stator core which is formed in an annular shape to surround the rotor and has a plurality of slots arranged in a circumferential direction and extending from one end to another end in a center axis direction, a conductor disposed in the slots, and a cooling unit which cools the conductor. Opening portions of the slots are formed in an inner peripheral surface of the stator core, the opening portions extend toward a downstream side in a rotation direction of the rotor at a time of regeneration from at least one end portions to intermediate portions in the center axis direction, and the cooling unit cools portions of the conductor which are located at the same positions as the intermediate portions of the opening portions in the center axis direction.