Information recording and reproducing device and information recording and reproducing method

An information recording and reproducing device that records and reproduces information in a recording medium, comprising:

• a recording section which records information in the recording medium;
• a reproducing section which reproduces the information recorded in the recording medium;
• and
• a deterioration detection processor which detects deterioration of a signal quality of the information recorded in the recording medium, wherein
• the deterioration detection processor:
• reproduces information recorded in a first area of the recording medium, with use of the reproducing section, to acquire first comparison information representing a signal quality;
• records information, with use of the recording section, in a second area of the recording medium different from the first area after the information recorded in the first area is recorded in the first area, and reproduces, with use of the reproducing section, the information recorded in the second area to acquire second comparison information representing a signal quality;
• and
• determines that the signal quality of the information recorded in the recording medium is deteriorated, in a case where the second comparison information represents a signal quality higher than that represented by the first comparison information.