To display a different picture corresponding to a current date by reducing capacity required for a hard disk by a simple method.

A personal computer(PC) 1 has a timer 2 for counting a date, a current date acquiring part 3 for acquiring a current date from the timer 2, a preceding starting date storing part 4 for storing a preceding date having started the PC 1 itself, a date comparing part 5 for judging whether the same contents as contents displayed at the preceding start can be displayed or not, and a file substituting part 6. A hard disk 7 storing the contents of display at least at the preceding start and a CD-ROM driver 8a are connected to the PC 1 and a CD-ROM having recorded at least all display contents is inserted into the drive 8. In the case of displaying content different from the contents displayed at the preceding start, display contents corresponding to the current date are read out from the drive 8 and stored in the hard disk 7.