A DA converter to reduce second-order harmonic distortion more precisely with convenient configurations. A DA converter including: a DA converting unit to input reference voltage and a digital value and output an analog signal according to the digital value based on the reference voltage; and a superimposing unit to superimpose, on the reference voltage, a superimposing signal based on the analog signal that is output from the DA converting unit, and a DA converting method are provided. The DA converter may further include a setting input unit to input setting regarding at least one of a superimposing amount and a sign of an analog signal to be included in the superimposing signal. Also, an adjusting apparatus and an adjusting method to adjust the DA converter are provided.