Twitter, a microblogging service, is now grabbing attention of people as a new channel. For deep understanding of this new service, this paper reports the characteristics of Twitter users in Japan, and the impact of media such as publications, and TV programs on Twitter community. To the best of our knowledge, this paper is the first to analyze mutual impact between Twitter, and other media quantitatively. In order for the analyses, we crawled user profiles whose language setting is Japanese, and conducted several analysis with well-known methodologies as conventional work did. We confirmed the characteristics of the collected user profiles. We observed the distributions of the number of friends, and the number of follows both follow power-law, and there exists the correlation between the number of friends, and the number of follows. Besides the collected user profiles, we also utilized closed caption data of TV programs in Japan, and other information on media picked up Twitter. We run a batch of matching these data outside Twitter with the collected user profiles, and concluded Twitter has been already widely spread among Japanese people, however, media have still huge impact on the growth of Twitter users. We also conjectured the impact is not one-sided, however, is mutual influence between Twitter, and other media.