An optimum power set value Pwp1 for Layer 1 obtained by an OPC is used as an initial value Pw21 of the OPC for Layer 2. At this time, an inclination Ia is obtained from an approximation line of a .beta. value for Layer 1 (recording power to the .beta. value) obtained by the OPC. From the .beta. value obtained by performing a test recording at the initial value Pw21 and the inclination Ia, an approximation line of a .beta. value for Layer 2 (recording power to the .beta. value) is obtained. Then, on the obtained approximation line, a laser power for providing a target .beta. value (.beta.t) is obtained, and set as an optimum power Pwp2 for Layer 2. Thus, an optimum power setting conforming to characteristics of a disc can be performed. As a result, setting the optimum power for Layer 2 can be performed more smoothly and quickly.