To realize the grasp of progress of students attending a lecture, a speedy change in contents, an efficient joint work by many producers, and timely information services.

In an additional information input device 3, additional information is inputted to a proper point while an information material 1 is being reproduced, and is stored in an additional information server 5. A continuous information reproducing device 4 starts reproducing the information material 1 on students' sides, and displays the reproduced video at any time. Then, when the additional information reaches a preset reproduction position, the reproducing device stops reproducing, and displays the additional information from the additional information server 5 with the reproduced video. As the additional information, for example, tests for grasping the progress of students can be mentioned. The additional information server 5 manages storage of additional information, marking processing of tests, storage of marking results, a reproduction start position in the continuous information reproducing device 4, a position for inserting the additional information, etc.