The aim of this study was to look at individual's psychological character, causes from home and a discrepancy among major factors to be addicted to smart-phone. Also, it was studied to find out how those factors could be influenced on the smart-phone addiction. Participants are 6-grade elementary students. What follows are the results from the study. First, it is shown that there is a discrepancy between group with addition to smart-phone, which was included 132 participants (33.2%) among the entire of 398 participants, and non-addiction group in accordance with the motive of smart-phone use, performance at school, an economic level, the level of parents' interest, a family atmosphere, the level of conversation with parents, self-respect, loyalty, loneliness, aggressiveness and frequency. The other appears that major factors for 6-grade elementary student to be addicted to smart-phone are graded to aggressiveness, frequency, self-respect, loyalty, the level of parents, loneliness, parents' control.