The current study sought to examine the relationships between reassurance seeking and mental health from the perspective of “emotionships”. High reassurance seekers repeatedly seek reassurance from significant others. Although previous studies reported that interpersonal rejection by significant others mediated relationships between reassurance seeking and mental health, the mechanisms underlying this relationship remain unclear. Thus, the current study examined the relationships between reassurance seeking and mental health using the framework of “emotionships”, which are the structures of interpersonal networks involved in emotion regulation. The findings of previous studies suggest that high reassurance seekers may have narrow interpersonal networks for emotion regulation, resulting in worsening mental health. The results of a questionnaire survey of 56 students indicated that those who engaged in reassurance seeking tended to have fewer emotional domains and interpersonal networks for interpersonal emotion regulation. In addition, interpersonal networks for emotion regulation were positively correlated with well-being. These findings indicate that maintaining interpersonal networks for interpersonal emotion regulation may be important to prevent the deterioration of mental health for reassurance seekers.