This study aimed to analyze the casual structure of the relationship between use motives and
psychological characteristics that affect smart phone addiction. It was found that the motive of social
relationship exerted a positive effect on self-control, while the motive of leisure time use had a negative
effect on self-control. It was also found that both motives of social relationship and leisure time use
had a positive influence on smart phone addiction. Self-control psychological characteristics, on the
other hand, were found to have a negative effect on addiction. The analysis of the mediate effects of
these factors exhibited that the motives of social relationship and leisure time use have partial mediate
effects. The current research has identified an indirect relation mediated through psychological
characteristics as well as a linear structural relation between use motives and addiction. This research
result shows that usage motive not only has simple linear structural relation with smart phone
addiction, but it also showed indirect phase of displaying self-control psychological characteristics
through smart phone addiction. Furthermore, the findings might suggest that use motives and
psychological characteristics be taken into consideration when creating prevention and rehabilitation
programs for smart phone addiction.