An error correction circuit and a folding ADC are provided. In the folding ADC,
the range of the input voltage to an upper ADC circuit and to a lower ADC circuit
is shifted by a predetermined voltage toward higher and lower electric potential
sides. The error correction circuit outputs the conversion result of the upper
bits as is, or corrects the conversion result of the upper bits by either subtracting
or adding 1 from or to the conversion result of the upper bits in accordance with
the least significant bit within the conversion result of the upper bits and in
accordance with the polarity of a code having different polarities between a period
in which the voltage level of one folding signal among a plurality of folding signals
output from the folding circuit is higher than the center level and a period in
which the voltage level is lower.