A vehicle AC generator includes a rectifier unit having plus cooling fin carrying a plurality of plus diodes, a minus cooling fin carrying a plurality of minus diodes, and a connection member disposed between the plus and minus cooling fins for insulating the two fins and connecting the plus and minus diodes. A plurality of U-shaped terminal members axially extend from the connection member which respectively guide the leads of the armature winding. Each of the terminal members has three longitudinal side walls forming generally rectangular cross-section, one end connected to the rectifier unit, the other end connected to one of the leads, and a heat-block portion having at least two of the side walls.