To enable the exact addition of postscript when the write-in of data is interrupted, by exactly detecting the final writing position of the data and hastening the start of the write-in of the data.

By a data transfer means 3, the data to be recorded are transferred to a light emitting means 2 while controlling the positional information on the data, and the data are recorded by the light emitting means 2 in the manner of irradiating the optical disk 11 with laser beams. When the error is generated and the laser beam output of the light emitting means 2 is stopped, this state is detected by a means 4 for detecting the stop of output and notified to a data transfer means 3, then the positional information on the data being transferred at the notified time point is stored in a positional information storage means 5 by the data transfer means 3.