In an apparatus for recording binary information on a flexible magnetic disk, a plate, is provided connected to an electric motor, for rotating the disk, and a spiral guide is formed on a first surface of the plate for moving a recording head radially with respect to the disk, in synchronism with the rotation of the plate and the disk. The improvement comprises an electronic circuit, which controls the angular speed of the motor, and quickly accelerates the motor, when the last binary information has been recorded on the disk, for shortening the time taken by the head to return to the rest position.