To provide a modulating method, a modulating device, an information recording medium and a demodulating method which can improve a reliability by introducing a RLL (Run-Length Limited) signal so that a LSB (Least Significant Bit) signal does not repeat 0 and 1, grasping the LSB of each cell as one signal string, preventing the LSB signal from being the highest frequency by encoding a run-length limited code to the position of the LSB and eliminating a signal (with small amplitude) of a weak power in high pass by making the LSB signal a low pass signal.

In the modulating method for information recording for recording information as multivalued information of a ternary or more in an information recording medium, when the number of bits of the multivalued information is defined as n bits, information in n-1 bits of a higher-order is set as it is, and in the least significant bits, encoding is performed with a run-length limited code in which the minimum reversal interval is two or more.