PURPOSE: To obtain stabler recording characteristics by holding a distance between a magnetic head and a recording medium constant and holding intensity of a magnetic field to be applied to an optomagnetic disk constant.

CONSTITUTION: An optomagnetic disk apparatus comprises objective lens position detecting means 21 for detecting a displacing amount of an objective lens 7 to be controlled at its focal position by an objective lens actuator 10 in response to a displacement of an optomagnetic disk 1 due to its surface fluctuations, etc., magnetic head position detecting means 22 for detecting a position of the head 14, and a magnetic head actuator 16 for controlling the position of the head 14 at substantially the same displacing amount as that of the lens 7.