To provide a display device capable of allowing a light emitting element
to emit light with a constant luminance while being free of an influence
of deterioration over time and capable of accurate gradation display and
high-speed writing of signal current to each pixel as well, in which an
influence of noise causing leak current etc. is suppressed, and a driving
method therefor. According to the present invention, plural pairs of
switch portion and current source circuit are provided. Each of the
plural switch portions is controlled in its switching operation according
to a digital video signal. When the switch portion turns on, the current
source circuit corresponding to the switch portion supplies current to
allow the light emitting element to emit light. The current supplied from
one current source circuit to the light emitting element is constant and
a value of current flowing into the light emitting element corresponds to
the total value of currents supplied to the respective light emitting
elements from all the current source circuits corresponding to the switch
portions in a conductive state.