Toward the highly information-oriented age, the Geological Survey of Japan (GSJ) has aggressively developed digitizing works of various types of geological map and prepared geological map database, for the purpose of supplying geoscience information to the society. A summary of geoscience databases that have been published or will be published in a short future by the GSJ is also reported. Furthermore, we introduce a simple GIS viewer software-GeomapZ. GeomapZ is designed for publishing geological database to a general user who does not use any GIS software on market. GeomapZ has the functions of viewing, printing, and processing geoscience databases. GeomapZ runs in Microsoft Windows and can read DLG-formatted vector data files, DEM-formatted elevation data files, raster image data files, and user data in text format. At last, we introduce some databases managed with GeomapZ.