PURPOSE: To prevent erroneous putting on of a recording medium and to improve the working efficiency, by reading discriminating information on the recording medium independently of the execution of a business program and visually displaying the content.

CONSTITUTION: A display section is a liquid crystal display which displays discriminating information written on a floppy disk FD, such as consecutive numbers of volumes and file names, etc., and, when discriminating information is written on plural records, an advance reading designating key designates the reading of the next record for successively reading records and displaying the content. When the floppy disk FD is mounted on a mounting mechanism, a control section receives a signal which indicates the mounting and performs the processing shown in Fig. (A). When the floppy disk FD is taken out, the control section performs the processing of Fig. (G) in the same way. When the advance reading designating key is pressed, a signal which indicates that the key is pressed is sent to the control section and the control section performs the processing of Fig. (C).