A recording and replaying device is provided in which a user can easily diagnose failure when a built-in storage device of the device fails. In a normal operation state, a microcomputer controls a signal path switching mechanism to connect a signal processing device and a hard disk drive (HDD). In an abnormal operation state, the microcomputer sets a USB interface device to effective state, and controls the signal path switching mechanism to connect the USB interface device and the hard disk drive (HDD), so that the hard disk drive is recognized by an external personal computer as a USB mass storage.