PURPOSE: To make narrow the deformation range of a flexible magnetic disc by arranging an introduction slider and a magnetic head along the running direction of the magnetic disc.

CONSTITUTION: The relative positions of an introduction slider 2, which is arranged to face the upper surface of a flexible magnetic disc 1, a lower magnetic head 3, which is arranged to face the top of an upper magnetic head 4 and the lower surface of the magnetic disc 1, and the top of an extracting slider 5, is so determined that the magnetic disc 1 meanders while being slightly warped. The introduction sliders 2 and 5 act to suitably push the magnetic disc 1 onto the tops of the heads 3 and 4 and to restrain the instable vibrations of the magnetic disc 1.