Until now, many kinds of persuasive applications have been developed, and latest persuasive applications have utilized users' contexts acquired by several sensors for more effective persuasion. Currently most applications assume that those applications run with special devices that are equipped with sensors for acquiring those contexts. The use of such special devices may deter would-be users because they do not have a habit of getting on such additional devices. In this paper, we introduce a persuasive application that uses users' contexts acquired by mobile phone. Through our experiences in the application, we clarify whether current mobile phone is enough to acquire users' contexts and to persuade users or not.