In order to supply controlled DC voltages to a plurality of loads at high efficiency by using smaller number of components, a multiple output DC-DC converter in accordance with the present invention comprises a first main switch 21, one terminal of which is connected to the negative electrode of an input DC power source 1, a first rectifying means 51 and a first smoothing means 61 connected to the other terminal of the first main switch 21, a second main switch 22, one terminal of which is connected to the positive terminal of the input DC power source 1, a second rectifying means 52 and a second smoothing means 62 connected to the other terminal of the second main switch 22, an inductor 31 connected between the other terminal of the first main switch 21 and the other terminal of the second main switch 22, and a control circuit 81 for driving the respective switches at predetermined ON/OFF period ratios.