Abstract: A head position controlling device in which the head position may be controlled accurately even with a magneto-optical disc having regions with different reflectance values. A gap sensor consisting of a light emitting element 5 and light receiving elements 6 and 7 are arrayed along the track direction of a magneto-optical disc to prevent unequilibrium in the volume of received light at the light receiving elements 6 and 7.

Abstract: A recording and/or reproducing apparatus into which a disc cartridge accommodating a disc is loaded and in which information signals are adapted to be recorded on or reproduced from the disc. A temperature sensor is provided within the apparatus for contacting with and sensing the temperature of the disc cartridge. By this temperature sensor, the temperature of the loaded disc cartridge is sensed and an output of a light source of an optical head is controlled on the basis of the sensor output to effect recording and/or reproduction of the information signals under an optimum operating state.