To provide a semiconductor device in which writing operation of signal current can be performed quickly in a current input type current source circuit.

A signal current is written after performing pre-charge operation. Therefore, writing operation is performed quickly. In the pre-charge operation, current is supplied to a plurality of circuits. At this time, magnitude of the current is made greater according to the number of the circuits to be supplied with the current. As a result, a steady state can be obtained quickly. In addition, the current may be supplied to a circuit other than the circuit which is a target of signal inputting when performing the pre-charge operation.