PURPOSE: To eliminate the adjustment of the correlative positional relationship of a pair of magnetic heads of a floppy disc apparatus.

CONSTITUTION: A delay circuit 11 is connected to an output line of an index sensor 10 of a double-sided floppy disc apparatus. The delay circuit 11 includes a first and a second delay informations to correct the positional relationship between a first and a second heads 2, 3 and the index individually. The first and second delay informations are alternatively used by a side select signal. Accordingly, the delay time of an index pulse is changed corresponding to the selection of the first, and second heads 2, 3. The positional shift of the first and second magnetic heads 2 and 3 is electrically corrected by the delay circuit 11.