Provided is a vehicle AC generator having a retainer attached on a bearing containing portion of a front bracket, thereby realizing temperature reduction in a bearing without deteriorating the cooling performance as a whole. In the vehicle AC generator, a front bracket 2 has a bearing containing portion 21 supporting a bearing 5 fitted therein, and an air inlet 22 that is provided along the outer circumference of the bearing containing portion 21 and allows cooling air from a fan 83 to pass therethrough. In addition, a retainer 15 is attached on the bearing containing portion 21, so as to cover the bearing 5. The retainer 15 has a planar shape, and has a fin 15b as a surface area increasing portion for increasing an area of contact with the cooling air, formed at a position facing to and outside the air inlet 22 in the shaft direction.