The purpose of this study was to find the characteristics of internet auction user groups by the levels of addictive tendencies among high school students. The questionnaire was conducted from December 16 to 23, 2008, and 288 high school students who were living in Cheongju area were selected. The main results were as follows. First, 13.4% of respondents were visiting internet site almost every day, and about 20% of them stayed more than 2 hours for visiting the internet auction site. Second, the price of purchasing goods through internet auction site(shopping mall) was less than 50,000 won. Third, the level of addictive tendencies of respondents was under average(2.08 out of 5 point scale), and about 10% of them evaluated by themselves as an internet auction. Fourth, relatively higher addictive tendencies group showed the characteristics such as lower self-esteem, higher depression, and higher feeling of isolation, internet related(general internet use, internet shopping, and internet game) addictive tendencies, and more often visiting and staying longer in internet auction sites and other internet sites.