The purpose of this study is to explore the Instagram users' behaviors since Instagram users are rapidly growing recently. This study is based on Bhattacherejee's (2001) IS Continuance Model, and try to propose a behavioral scale for Instagram users. Then, providing a research model to explore the relationship between the reasons they used Instagram, attitude and future intention. There are two steps in this study; first, exploring the patters of Instagram users and building the behavioral scale. We take quantity methodology and in-depth interview since in-depth interview could help to find those constructs which are not found yet. Second, a survey was completed on university campus, and structure equation model method was applied in this study. Since majority of Instagram users are young generation, the study was aimed at college students. A university was selected for the participant, and stratified random sampling was adopted with two controlled variables (gender, and college). A total of 395 questionnaires were completed in the university. The findings indicated that the motivation of Instagram users were different from Facebook users. Based on the in-depth reviews, participants had two main reasons to addict with Instagram. One was for "interesting" and the other was for social bounds. For the theory based model, results showed mostly supporting the relationships. Results could also be applied for the related industries, for creating a marketing platform (e.g. Instagram) to promote new service or product. Nowadays, Instagram is newly virtual social media compare to Facebook, and the users' behavioral patterns were different from them. Therefore, it is an essential issue should be focus for the society.

Keywords: Social Network; IS Continuance Model; Instagram