A display element included in a display device is provided with a TFT
circuit portion and a pixel aperture portion to which an organic EL
element material is applied and which emits light in accordance with a
current from the TFT circuit portion, as well as a scanning signal line
electrode, a data signal line electrode and a power source line
electrode. The resistance Re of the power source line electrode can be
reduced, because the electrode width at a portion where the power source
line electrode is in contact with the pixel aperture portion is larger
than the electrode width at other portions. The resistance ratio Rx/Re
between the electrode resistance Re and a combined resistance Rx of a
current path from the power source line electrode through the pixel
aperture portion is at least 10.sup.5. Thus, a display element and a
display device are realized, which have little luminance variation within
the display screen, which have a high numerical aperture, a high light
emission efficiency and a long lifetime.