A constant-voltage generating circuit includes: a reference potential generating unit; first and second amplifier units whose outputs are respectively connected to the output line; and a low-pass filter, and wherein first and second operation periods are repeated, one alternating with the other, the first amplifier unit stores offset voltage of the first amplifier unit during the second operation period, and produces an output, during the first operation period, that brings the first potential and the second potential equal to each other by canceling out the offset voltage using the stored offset voltage, and the second amplifier unit stores offset voltage of the second amplifier unit during the first operation period, and produces an output, during the second operation period, that brings the first potential and the second potential equal to each other by canceling out the offset voltage using the stored offset voltage.