A rectification processor includes rectifier elements that control charge to batteries independently for each of the batteries. A charge-state detector detects charge states of the batteries from their voltages, and determines whether to select the batteries for charging in a half-cycle determined beforehand in accordance with the detected result. A synchronous signal detector detects a signal synchronized with the phase of the 3-phase alternate current (AC) generator from the 3-phase AC generator, and outputs a synchronous signal. A charge controller controls the charge in the rectification processor in synchronization with the 3-phase AC generator according to the synchronous signal from the synchronous signal detector, and, in accordance with the charge states of the batteries output from the charge-state detector, controls charge amounts to the battery/batteries that was determined for selection.