To reduce time for writing a target voltage in the gate of a driving
transistor. In a first period, a transistor 211 is switched on to allow a
driving transistor 210 to function as a diode and transistors 212 and 213
are switched on to electrically connect the drain of the driving
transistor 210 to a data line 112, to which an initial voltage is
applied, such that the initial voltage is applied to the gate of the
driving transistor 210. In a second period, a transistor 212 is switched
off such that the gate of the driving transistor 210 is maintained to
have an off voltage corresponding to the power source. In a third period,
the transistor 211 is switched off such that the voltage of the data line
112 is converted into a grayscale voltage to maintain the gate of the
driving transistor at the target voltage. In a fourth period, the driving
transistor 210 flows the current corresponding to the maintained gate
voltage to an OLED element 230.