Many groupware systems have been used for communication between personal computers (PCs) in companies. However, the demand for groupware systems is growing. Cue to the spread of mobile phone users and systems, new mobile phone groupware systems are needed. In groupware systems, the location information function which is used to find the location of group members is a very important function for smoothing group activities. In this paper, we propose a mobile phone groupware system using location information function. By resolving problems of the location information function of the Devora system, we improve the performance of the proposed mobile phone groupware system. The evaluation results show that our system operates smoothly and the communication cost is decreased.