We have developed a support system for collaborative learning in environmental education by using distributed virtual environment accessible from real and virtual worlds. With this system, learners in the real world and experts in a virtual world can communicate with each other while sharing not only a 3D virtual world implemented with VRML, but learners' achievements and experts' knowledge. It also realizes databases of real experiences, education supported by valuable knowledge given by experts from all over the world, and virtual tours to inaccessible natural environment. Furthermore, the system is expected to raise consciousness of environmental protection by providing users with knowledge and information on the environment accumulated in the learning process. The system makes all these functions possible, which have been difficult to realize with conventional environmental education.