On CAI in earth science education, the authors have a principle that interests of students in natural materials and phenomena must be promoted by the effective use of computer. Based upon the principle, BASIC programs for drawing the three-dimensional topographic map of western Hiroshima Prefecture are developed. Using the programs, given are earth science instructions in junior and senior high schools. Through the instructions, the students are progressed to be interested in the topography of their native land. Additionally they seem to inflame vivid imagination for earth science phenomena.