A cooling structure includes a rotating electrical machine (1) that has a stator (3), the stator including plural split cores (4) annularly combined, and a shrink-fitted ring (5) mounted to the outer periphery of the plural split cores (4) for integrating the plural split cores (4), and a case (10) that accommodates the rotating electrical machine (1) therein, the shrink-fitted ring (5) includes a cylindrical portion (6), and a flange portion (7) that is provided at one end of the cylindrical portion (6), the case (10) includes an accommodating portion (11) which has an inner peripheral wall (11a) whose inner diameter is larger than the outer diameter of the cylindrical portion (6) and smaller than the outer diameter of the flange portion (7), and in which accommodates the stator (3), a first wall face (12) extending outward in the radial direction from the end of the inner peripheral wall (11a) where the flange portion (7) is arranged, the flange portion (7) being mounted to the first wall face (12), and a second wall face (13) extending inward in the radial direction from the end of the inner peripheral wall (11a).