A level switch circuit receives a digital input signal, and generates a level signal having a voltage level that corresponds to the value of the input signal thus received. A buffer circuit receives a level signal, and outputs the level signal via an output terminal thereof. A bias current generating circuit generates a bias current including a DC component having a constant level and a variable component that changes according to the input signal, and supplies the bias current thus generated to a buffer circuit. The bias current generating circuit detects an edge of the input signal, and raises the bias current by a predetermined amount for a predetermined period of time after the edge thus detected.