PURPOSE: To automatically control with a sequence controller by utilizing the whole range of available digital value or the whole dynamic range of a recording medium or both of them.

CONSTITUTION: In the case of recording a digital signal with the recording medium in order to prepare the master of an optical disk, after previously storing the largest digital record level value, a digital source parameter value, corresponding to the largest signal level of a complete first path 12T of a source material 12, is determined. And a control signal is pulled out by determining a scaling control signal in accordance with the relative value of a digital record reference parameter value and digital source parameter value. Thereafter, the source material 12 reproduced between a second path 12C is scaled inn a straight line shape in accordance with the control signal, and the scaled digital signal is recorded on the optical disk.