The psychological impact of social media has long been of interest and numerous studies have been conducted. In particular, it has recently been pointed out that in the process of viewing positive content posted by other users, they may compare it with their own lives and experience negative feelings. This chapter introduce the findings that such negative effects of social media are also observed among working adults who gather information for career development. Furthermore, this chapter focuses on companionship and self-concept clarity as factors necessary to mitigate these effects, and discusses how to overcome the negative effects of SNS based on the findings of previous studies.