Abstract: The apparatus records and reads binary information on a magnetic disk having magnetizable surfaces subdivided into a plurality of concentric tracks in which the information is recorded in block form (sectors). A first electric motor rotates the magnetic disk at a substantially constant angular velocity, and a second motor (22) of stepping type is operable to position the magnetic recording and reading heads (16, 17) with respect to the recording tracks of the disk. On each track, each block of binary information contains prerecorded burst information which, when read by the corresponding magnetic head, is capable of causing micrometric rotary adjusting movements of the stepping motor to bring the magnetic head into precise alignment with the selected recording track and to hold it in that position. Thus amplitude information from two bursts either side of the center line of the track is compared (52, 55, 59, 58) to provide a signal (.mu.STEP) when the amplitude discrepancy exceeds a threshold, and a signal (.