Abstract
Authors are developing a software tool, Keity, that is an educational tool for undergraduate students to start studying architectural environment engineering smoothly, and opening it to the public through internet. This paper reports purpose to develop Keity, outline of the system, and major algorithm of program function. Currently textbook is the main educational tool, but computer software will become important tool for education as spread of computer in the school. Through developing Keity, we aim at proof of possibility of software as educational tool.