A data reading apparatus includes: a medium-transporting unit configured to transport a medium on which magnetic ink characters are printed; a reading mechanism configured to read the magnetic ink characters printed on the medium in the form of a magnetic waveform; a correction-value storage unit configured to store a correction value inherent to the data reading apparatus, the correction value having been calculated from an error determined by comparing a reference magnetic waveform acquired by reading reference magnetic ink characters printed on a reference medium in a reference data reading apparatus, with the magnetic waveform actually acquired by reading the reading mechanism; a correction unit configured to correct, by using the correction value, the magnetic waveform acquired when the reading mechanism reads the magnetic ink characters printed on the medium; and a decryption unit configured to decrypt the magnetic ink characters printed on the medium, in accordance with the magnetic waveform corrected by the correction unit.