An evaluation too for collaborative learning has been developed. The tool is based on communication which occurs during the collaborative work. The tool consists of two sub-tools: a monitoring tool and a scoring tool. The monitoring tool can evaluate automatically students' behaviors during collaborative work. The scoring tool can score automatically output products such as reports. The two tools are established by natural language techniques: TF/IDF method, vector space model method. As a result of experiments, we confirmed that the tool was able to provide rough evaluation of individual student in the collaborative learning. In addition, we confirmed that the tool has a weakness in the evaluation's accuracies when students copy & paste sentences from web-sites to their reports.