To surely attain the virus check of a floppy disk to be handled by its own device.

When an access request from an OS to an FD drive is issued, any access to the drive can be forcedly inhibited, and whether or not the FD mounted on the drive is infected by virus can be detected by driving a virus detecting driver while the access is forcedly inhibited. When it is detected that the FD is not infected by any virus, the forced inhibition of access to the FD drive is released so that access to the FD can be performed, and when it is detected that the FD is infected by virus, the forced inhibition of access to the FD drive is maintained, and warning that the FD is infected by virus can be outputted.