In first and second gate electrodes constituting a gate electrode, the gate length of the second gate electrode is set shorter than the gate length of the first gate electrode and short enough to produce the short channel effect. The threshold voltage of a second transistor corresponding to the second gate electrode can thereby be made lower than the threshold voltage of a first transistor corresponding to the first gate electrode. When the same voltage is applied to the first and second gate electrodes, an electric field concentration at the channel edge on the drain side is reduced. This in result reduces the channel length modulation effect.