To provide an electro-optical device, a driving method therefor, and an electronic apparatus which can accurately control the brightness of electro-optical elements in accordance with the signal level of a data signal. A brightness detection circuit 15 is provided which samples power-supply current Io every time one scan line is selected and which converts the power-supply current Io into a digital voltage signal DS having a digital value corresponding to the power-supply current Io. A light-emission-period control circuit 16 generates light-emission-period control signals H1 to Hn in accordance with a light-emission-period adjusting signal F corresponding to the digital voltage signal DS and outputs the light-emission-period control signals H1 to Hn to corresponding control-signal supply lines G1 to Gn. Further, light-emission-period control transistors of the pixels 20 which are connected to the corresponding control-signal supply lines G1 to Gn are on/off controlled, thereby controlling the light-emission period of the electro-optical elements.