Optical recording method and optical recording medium

An optical recording method for recording mark length-modulated information with a plurality of recording mark lengths by irradiating a recording medium with a light, the optical recording method comprising the steps of:

• when a time length of one recording mark is denoted nT (T is a reference clock period equal to or less than 25 ns, and n is a natural number equal to or more than 2),
• dividing the time length of the recording mark nT into
• η1T, α1T, β1T, α2T, β2T, . . . , αiT, βiT, . . . , αmT, βmT, η2T
• in that order (m is a pulse division number;
• Σhd i(αi+βi)+η1+η2=n;
• αi (1≦i≦m−1) is a real number larger than 0;
• βi (1≦i≦m−1) is a real number larger than 0;
• βm is a real number larger than or equal to 0;
• αi+βi (2≦i≦m−1) or βi−1+αi (2≦i≦m−1) is kept constant independently of said real number i;
• and η1 and η2 are real numbers between −2 and 2);
• radiating recording light with a recording power Pwi in a time duration of αiT (1≦i≦m);
• and
• radiating recording light with a bias power Pbi in a time duration of βiT(1≦i≦m−1), the bias power being Pbi<Pwi and Pbi<Pwi+1;
• wherein the pulse division number m is 2 or more for the time duration of at least one recording mark and meets n/m≧1.25 for the time length of all the recording marks,
• further wherein when the same pulse division number m is used on at least two recording marks with different n values, a difference mark length is formed by changing at least one of β1, βm−1, and βm.