POWER SOURCE DEVICE

An electrical generator is connected with a first end of DC/DC converter and an electric storage section is connected with a second end of the converter. An output voltage detecting circuit is connected to the electrical generator, and a control circuit is connected to both the DC/DC converter and the output voltage detecting circuit. The electrical generator raises an adjusting voltage Va at an output terminal to a first predetermined output voltage Vdc1 at a timing when regenerated electric power is produced. Control circuit 35 controls an output voltage Vd to be a lower control voltage Vdk which is lower than the first predetermined output voltage Vdc1. The lower control voltage Vd is set at a value which allows a main power supply to be charged maximally with the regenerated electric power.