A source of a driving transistor for driving an organic EL element
functions as a first capacitance electrode layer. A second capacitance
electrode layer is formed on the source through a gate insulating film of
the driving transistor. The second capacitance electrode layer is formed
with the same layer and by the same process as the gate electrode. A
third capacitance electrode layer is formed extending over the second
capacitance electrode layer through the interlayer insulating film. The
third capacitance electrode layer is formed with the same layer as the
drain electrode and the drain signal line. The third capacitance
electrode layer is connected to the source of the driving transistor. The
forming area of the storage capacitance element for holding the video
signal supplied to the gate of the driving transistor can be thus
reduced, improving display quality as well as extending life span of the
organic El element.