An oversampling A/D converter includes a first filter including a first resistive element, a first capacitive element, a second resistive element, an operational amplifier, and a second capacitive element; a second filter receiving an output of the first filter; a third filter including a third resistive element, a third capacitive element, and a fourth resistive element; a quantizer receiving an output of the third filter and generating a digital signal; and a D/A converter converting the digital signal to an analog current signal. The D/A converter inputs the generated analog current signal to an inverting input terminal of the operational amplifier.