1. A method for encoding binary data, the method including the steps of: performing encoder mapping for converting at least one data word having N data bit(s) into at least one binary modulation word having M data bit(s), wherein redundant information is provided so that a predetermined data word can be translated into a plurality of modulation words; and selecting a predetermined modulation word from among the plurality of modulation words obtained through the encoder mapping step, according to a look-ahead determination criterion method, wherein the look-ahead determination criterion method includes the steps of: recording a current data word to be modulated and a predetermined number of future data words in either an original form or in a pre-encoded form; making a path search for evaluating a running digital sum (RDS) for a combinational tree whose space is expanded by a multiplier of the modulation words generated by performing the encoder mapping for the recorded current and future data words; and making a determination to select an encoding mapping method suitable for the current data word to be encoded by determining a path nearest to bounds of the RDS of the path search, wherein a low-frequency component of a resulting binary modulation sequence is suppressed so that the value of a first-order spectrum becomes null at a frequency of 0 Hz.