<p>A circuit (10) composed of a plurality of n-channel transistors includes a transistor (T1) in which an input signal is inputted to a drain terminal and an output signal is outputted from a source terminal and a transistor (T2) in which a control signal (D) is inputted to a drain terminal and whose source terminal is connected to the gate terminal of the transistor (T1). The gate terminal of the transistor (T2) and the source terminal of the transistor (T2) are connected with each other. Accordingly, a semiconductor device which is composed of conductivity type transistors that are identical and which is not affected by a noise and a display device including it are provided.</p>
