A clock signal in synchronization with a data writing signal, every scanning line, which is supplied from a light-emitting control circuit 4 to a scanning driver 6, is supplied to an oscillator 12 which generates a reference switching signal, according to a PWM method, in a DC-DC converter 8. Thereby, the timing at data writing every scanning line is in synchronization with the phase of a ripple component superimposed on a driving voltage Va from the DC-DC converter 8. Accordingly, a problem that there is caused a state in which light-emitting intensity is different every scanning line can be solved because the same voltage Vgs between a gate and a source is supplied every scanning line to a light-emitting driving transistor Tr2 at any time even if the ripple component by switching of the DC-DC converter is superimposed on the driving voltage Va. Thereby, a problem that the display quality of images is remarkably reduced can be prevented in a light-emitting driving operation of a display panel, wherein the operation has a configuration in which an organic EL element with a light-emitting intensity characteristic of a current dependence type, for example, is used as a pixel.