For controlling DC-DC converters conforming to voltage mode control system and current mode control system, in multi-output power supply, first converter section 2 is configured that first detection circuit 31 outputs first control signal, that first oscillation circuit 32 outputs first triangular wave signal and clock signal, and that first pulse-width modulation circuit 33 drives first switch by comparing first control signal with first triangular wave signal. Second converter section 4 is configured that second detection circuit 34 outputs second control signal, that second oscillation circuit 35 outputs second triangular wave signal synchronized with clock signal, that current detection circuit 36 outputs current signal of second inductor, and that second pulse-width modulation circuit 37 turns ON second switch in synchronization with clock signal and turns OFF second switch by calculating or comparing second control signal, the second triangular wave signal and current signal.