A multi-output power supply device includes a first power switch, a first switch controller that controls the first power switch, a transformer that transforms a power supplied from the first power switch, first through Nth output circuits connected to a secondary side of the transformer, where N is a positive integer greater than 1, a second power switch that switches the power output from one of the first through Nth output circuits, a second switch controller that controls the second power switch, a feedback circuit that feeds back output voltages of the first through Nth output circuits, and a feedback compensation circuit that performs a switching operation complementarily with the second power switch to compensate for a resistance of the feedback circuit. Accordingly, when power output to one of the output circuits is blocked, the multi-output power supply device can stably control the power output to the other output circuits.