In this paper, we propose a personality estimation application for Twitter client in smartphone. This application enables user to know the personality of other Twitter accounts. In this application personality estimation is performed by the text classification method from tweet data. In the demonstration experiment with 44 subjects, our proposed application proves its effectiveness especially for the users in their 20s or Twitter experienced users in entertainment use. Both subjective and objective evaluations show that the personality information in social media makes some contribution to build a new connection and to stimulate the social media use.