A data demodulation method may include converting an analog signal into a digital signal; detecting a peak point of a reproduced signal; creating a plurality of preliminary data rows for creating demodulated data; and creating demodulated data. The preliminary data rows may include the first individual data to be identified on the basis of the interval, and are formed of the first individual data of plural bits. Creating a plurality of preliminary data rows may use a template listing part of, or all of, a plurality of bit patterns being formed of second individual data.