PURPOSE: To miniaturize the above device without impairing the function to impress magnetic fields by forming a permanent magnet to an hour glass shape which is a bar shape and has the sectional area in its end part larger than the sectional area in the central part.

CONSTITUTION: The permanent magnet 8 is of the square bar shape formed long in the radial direction of a disk and is formed to the hourglass shape having the sectional area on both end sides larger than the sectional area in the central part. Namely, the sectional area is large even at the ends and, therefore, the decrease in the magnetic field intensity is suppressed and the magnetic field intensity necessary over the entire length of the magnet is maintained. The permanent magnet 8 having about the length L' slightly longer than the effective radius l of the recording part of a magneto-optical recording medium 1 is consequently necessitated to be used. The size over the entire part of the magneto-optical recording device is reduced in this way.