This study researched why the students are addicted to mobile phone and the difference of motive and behavior pattern, depression, self-contentment and an impulse of mobile phone between addictions and non-addictions. The study researched 501 students in Seoul and other 6 capital areas: 254 male and 247 female. The study made the questionnaire referring to Jang, Hye-jin(2002) and Yang, Sim-yeong(2002)'s measure of Internet addiction of Young and also referred to CES-D, which is a measure of depression of Korean edition and Jeon, Byeong-jae(1974)'s the measure of self-contentment, which is adapted from Rosenberg(1965) and Lee, Hyeon-su(1992)'s the measure of impulse of BIS 2 edition, which is adapted from Barratt Impulsiveness Scale. The study also separated the addict top 25% and low 25% and applied n=129 and n=126 each them. In the research by demographic character, there was a significant meaning between age and average connection of Internet. There, the study operated the multi-level crossing analysis to research using motive and act between each group. The result is that the addicted user group started to use mobile phone earlier than the non-addicted user. And they have also changed more. The addicted group's average using phone time was 175.6, and the call time was 31.5, and the SMS was 66.5 times, and their saved phone numbers were 108.9. However, the non-addicted group was very different with that: their result was 68.3, 16.3, 24 and 69.7. And the study shows the result that 82% of the addicted group said that they always turn on the phone in class. The rate is much higher than the non-addicted group's 62.7%. Further more the former one has more an experience of using phone in class. The average phone bill was 39,212 won and 27,083 won. And they also have more an experience of delay. In the T-test, the addicted group was much higher rate of depression and impulse. The study operated the regression analysis regarding that the significant statistic variable was independent variable, and the addicted group and the non-addicted group were parameterize by the variant analysis. The significant elements of addiction were classification of school in the demographic statistic variables and total call time, the number of time of purchase a phone, the average using phone time a day, the average call time a day, the memorized phone numbers and experience of using phone in class in the using motive and act, and the positive aspects of using phone were that they can blow up the stress and call anywhere. However, the negative aspects were defrayment of using phone and the unease when they don't have a phone. In the mental health aspect, depression and impulse were connected with addiction.