An analog-to-digital converter includes an input-signal chopping switch, an integrator, an output chopping switch, a quantizer, and a feedback switch. The integrator is located after the input-signal chopping switch. The integrator includes an operational amplifier, an integral capacitor, and an integral-capacitor-chopping input switch being at on an input side of the integral capacitor. The output chopping switch is on an output side of the operational amplifier. The quantizer is located after the output chopping switch. The feedback chopping switch is in a feedback path from an output of the quantizer to an input of the first integrator. The input-signal chopping switch, the integral-capacitor-chopping input switch, the output chopping switch, and the feedback chopping switch execute chopping at an identical frequency. The output chopping switch sets a polarity of an input value of the quantizer to be identical before and after the chopping.