There have been continuous efforts for developing the automatic mechanical design system to increase the efficiency o f the tedious design process. However, these efforts have been concentrated on single platform application. Hence, the developed systems have been available only in a designated place and time and have been difficult to modify. It is proposed in this study that a web-based design system is developed to offer more reliability and convenience without any restriction o f time and place. The developed system is programmed based on Java, and the architecture o f the system has object-oriented features o f Servlet and JSP and is independent on any operating systems. The developed system has been applied to the initial design o f multi-stage gear drives, but however as the framework of the developed system is quite versatile, its application to automatic design o f any mechanical system or evaluation can be easily expected.