The present study aimed to examine the relationship of social anxiety and social skill to the use of mobile phone, social network, and mental health. The mobile phone is available when we do not want to meet others because of feeling of communication stress. A total of 225 freshman completed questionnaire at both undertaken April and July. As result, high social anxiety and low social skill group tend to use the mail more than other groups. Their tendencies might be caused by their avoidance from interaction of others. They were worse psychological health and not satisfied with their new friends than other groups. These result show that social anxiety and social skill have relation of use of mobile phone, social networks, mental health.