An automotive alternator is provided that reduces exclusive circumferential space for a regulator assembly inside a rear bracket, and that also increases performance in cooling the regulator assembly and a rectifier by ensuring that flows of air that cool the regulator assembly and the rectifier do not interfere with each other.An approximately C-shaped rectifier is disposed in a vicinity of a rotating shaft, and a regulator assembly is disposed between two end portions of the approximate C shape of the rectifier. A brush holder portion, a regulator circuit housing portion, and a connector portion that constitute a regulator assembly are positioned such that respective center lines thereof are in a common plane that includes a central axis of the rotating shaft. A partitioning wall is disposed so as to project from an inner wall surface of the rear bracket so as to separate a rectifier cooling airflow passage for cooling the rectifier and a regulator circuit cooling airflow passage for cooling the regulator circuit by stopping circumferential flow of air that is sucked in through the suction aperture to cool the rectifier and the regulator circuit respectively.