A driver circuit for a display device includes NOR circuits on the input side of switches for controlling precharge of data signal lines and selected pixels connected to the data signal lines. While a video signal is written onto a data signal line, a signal instructing precharge of another data signal line is inputted from a shift register to the NOR circuits. A simultaneous precharge instruction signal is inputted from outside to the NOR circuits. According to this arrangement, precharge is performed in both a period in which a video signal is supplied to a data signal line and a period in which no video signal is supplied to any of the data signal lines. As a result, it is possible to perform precharge even with a precharge power source having relatively low driving capability, and to precharge the signal supply lines of the display device sufficiently.