A vehicle alternator is disclosed having a stator, a rotor, a frame surrounding the stator and the rotor, a bowl-shaped end cover mounted on the frame and defining an electric component-part compartment, a brush unit held in sliding contact with slip rings of a rotary shaft, and a rectifier unit. The rectifier unit includes an insulating terminal block radially extending in face-to-face relation to the one end face of the frame, a positive-side cooling fin carried on one surface of the insulating terminal block, and a negative-side cooling fin carried on the other surface of the insulating terminal block. At least one of the insulating terminal block and the end cover has a heat shield plate member laterally extending through a radial space between the cooling fins and the brush unit in a direction substantially parallel to the axis of the rotary shaft.