An A/D converter includes an adjusting circuit to adjust a total of an amount of change of ΣΔ modulated data output from a ΣΔ modulator and an amount of change of dummy data to be constant, and a level converting part supplied with the ΣΔ modulated data. The level converting part includes a first level converter to output the ΣΔ modulated data by converting a level of the ΣΔ modulated data, and a second level converter to receive the dummy data from the adjusting circuit and interpolate dummy noise, in order to cancel a frequency dependence of noise with respect to the ΣΔ modulated data.