The variation of characteristics of transistors occurs. The present invention is a signal line drive circuit having a plurality of current source circuit corresponding to a plurality of wirings, a first and a second shift registers, a latch circuit, the foregoing plurality of current source circuits have capacity means and supplying means, respectively, characterized in that the foregoing capacity means converts a supplied current into a voltage according to a sampling pulse supplied from the foregoing first shift register, the foregoing supplying means supplies a current corresponding to the foregoing converted voltage according to a video signal, and the foregoing latch circuit operates according to a sampling pulse supplied from the foregoing second shift register.