Provided is an encoding apparatus including an encoding unit that converts, based on a first conversion rule group according to which a total value for a base-K symbol sequence is X and a second conversion rule group according to which the total value for the base-K symbol sequence is −X among conversion rule groups for converting an L-bit bit sequence into the base-K symbol sequence (K>2) of N/2 symbol, an M-bit (M≧2*L) bit sequence into the base-K symbol sequence of N symbols. When converting the M-bit bit sequence into the base-K symbol sequence of N symbols, the encoding unit converts a first-half N/2 symbol based on the first conversion rule group and converts a second-half N/2 symbol based on the second conversion rule group.