PURPOSE: To provide a gain adjustment circuit for bipolar output of a D/A converter where the movement of offset doesn't occur by obtaining a bipolar output without a level shifter by an analog multiplexer in the circuit where a unipolar D/A converter is used to obtain the bipolar output.

CONSTITUTION: The most significant bit of a voltage setting register 3 is used as a polarity selection signal, and data except the most significant bit is taken as input data of a D/A converter 4 and is converted into an analog current. This current output is converted into a voltage by an I/V conversion circuit 7, and this output voltage and the polarity inverted voltage are taken as positive and negative bipolar input voltages of an analog multiplexer 9, and the polarity of the output is selected by the most significant bit of the voltage setting register 3.