We presented an environment for spatial information sharing in the previous notes. The basic concept is that contents holders can submit up-to-date information on their under-sheet map and others can view them on their favorite map. In Japan, more than 63 million mobile phones are in use and most of them called KEITAI. Many such phones have internet access capabilities. Then, there are chances to get up-to-date information by KEITAI. This paper describes the concept of the spatial information sharing for mobile phones, and discusses its potential applications.