The spread of the Internet has made it much easier for young people to come into contact with obscene harmful information. The appearance of smartphones which are not always effective at filtering out such information supports this tendency, and new measures to counter this threat are urgently needed. This paper reports on the latest trends in research from abroad on mass communication effects which deal with sexually harmful information, and analyzes the special characteristics of the effects such information may have over the Internet and the limits of these study.<br>It is suggested that obscene information is not always harmful, but that what makes it harmful is whether images of sexual violence are depicted and how it shows the reaction of the woman who is involved. We must pay more attention to the actual situation caused by the characteristics of the Internet, including the development of computer graphics and the interactivity of community sites.<br>As there is a limit to how far we can depend on only technical regulation for measures to counter obscene harmful information on the Internet, we must consider new legislation and hope for better media literacy education at home and at school which allows young people to critically understand the potential distortions of sexually obscene information and the special dangers of the Internet.