To surely prevent the illicit use of teaching material contents by laying the delivered teaching material contents into a non-usable state after the expiration of the usable period.

The received teaching material contents are stored in a teaching material server. The slippage of date is calibrated on the basis of the information for delivery date in step S72. The start date of use is set in step S73. The teaching material contents are unusable up to the start date of use. Whether it is the start day of use or not is monitored in step S74, and when it comes to the start date of use, the teaching material server can be used. It is displayed that the teaching material server is usable in step S75. The countdown of the use time from the start date of use is started in step S76, and whether the usable period expired or not is determined in step S77. When the usable period expired, the teaching material contents are deleted from the teaching material server and a terminal to prevent the illicit use.