PURPOSE: To provide an optical disk device preventing failure due to the physical change of an optical disk and recording or reproducing excellently by controlling so as to hold the temperature of the surrounding of the optical disk to a proper temperature.

CONSTITUTION: When a drive instruction is outputted to a Peltier element drive circuit 9 from a control circuit 10, the temperature in a case 6 is measured by a temperature senser 7, and the measured temperature is inputted to the Peltier element drive circuit 9. When the measured temperature is out of a reference range, a Peltier element 8 is energized and the inside of the case 6 is cooled or heated.