To dynamically generate video relative information relating to scenes of video and to display them in timing to the video by receiving the result of retrieval from an information retrieval device based upon synchronism definition information having no relative information defined and dynamically generating new synchronism definition information having the result defined as relative information.

A synchronism definition information generating means 15 is a means which is called by a terminal device 3 through a communication medium 2 to dynamically generate relative information on video and the synchronous contents of the video and relative information and has a video relative information generating means 151 and a synchronous content generating means 152. The video relative information generating means 151 requests the information retrieval device 4 to perform retrieval through the communication medium 2 by using a communication control means 11 according to synchronism definition information having no relative information defined, receives its result through the communication medium 2 by using the communication control means 11, and dynamically generate new synchronism definition information having the result defined as relative information to generate the synchronous contents of the video and relative information.