Patent ID: 7154826

Claim:
An information-recording medium for recording and reproducing information thereon, the information-recording medium comprising: an information-recording portion on which the information is recorded by being irradiated with a light beam having a recording power Pp and an erasing power Pb lower than the recording power Pp and on which the information is reproduced by being irradiated with a light beam having a reproducing power Pr lower than the erasing power Pb; and a control data portion, wherein: information for determining an optimum erasing power Pb from a minimum erasing power Pb 1 which satisfies Pr<Pb 1 <Pb and a maximum erasing power Pb 2 which satisfies Pb<Pb 2 <Pp is previously recorded on the control data portion, and wherein the information for determining the optimum erasing power Pb from Pb 1 and Pb 2 is α, which is represented by an expression of Pb=α×Pb 1 +(1−α)×Pb 2 .