There is provided a plasma display device. The plasma display device includes a plasma display panel (PDP) and a driving unit for generating driving signals for driving the PDP. A period in which sustain signals are supplied to the PDP includes a first period in which sustain signals supplied to the PDP gradually increase from a reference voltage to a first voltage, a second period for sustaining a second voltage higher than the first voltage, a third period gradually falling from the second voltage to a third voltage higher than the reference voltage, and a fourth period for sustaining the reference voltage. The length of the first period is shorter than the length of the third period. The first switch is turned on at a point of time before the magnitude of current that flows through the inductor reaches a maximum value and then, becomes 0 in the first period. In supplying the sustain signals to the PDP, the point of time where the sustain voltage sustain period or the reference voltage sustain period starts is controlled so that the driving margin of the PDP can be secured enough without remarkably increasing the power consumption for the PDP and that the high resolution PDP can be driven at high speed.