PURPOSE: To perform excellent recording or reproduction by providing a detecting means which detects the defective shape or chucking of the hub of a floppy disk and when defective chucking is detected, immediately stopping the rotation of a motor.

CONSTITUTION: The 1st detecting means 9 which continuously checks the rota tion of a video floppy disk (VF) 3 for variation during the first one or more turns after a spindle motor 1 rises and the rotation of the VF 3 is locked in is provided, and when the means 9 detects abnormality, an error signal is gener ated and the rotation of the VF 3 is stopped. If a disk drive device is brought into contact with the VF 3, the rotation of the VF 3 varies at the point where the disk drive device is brought into contact with the VF 3 during one turn of the VF 3. Therefore, when the rotation of the VF 3 is continuously monitored for at least one turn after the rotation of the VF 3 is locked in, the contact between the VF and disk drive device can be detected. Therefore, excellent recording or reproduction can be performed.