It is very important for design and construction of complete dentures to evaluate the condition of residual ridges of edentulous patients objectively and precisely. The authors have been developing a shape measurement system for residual ridges. In this study, the outline of the system is described and the accuracy of the system is evaluated. The system consists of a high precision laser displacement meter, a working table and its controller, and a personal computer. The working table, on which a plaster model is placed, can move until the end of the moving range at a speed of 0.7 mm/sec. The height of the plaster model was measured intermittently with a frequency of 7 points/sec. To determine the accuracy of this system, experimental plaster models, which simulated the simplified shape of residual ridge, were measured and analyzed. The measurement error was 2.5%, which seemed to be highly accurate. The accuracy of the measurement decreased with the darkness of the color of the plaster model.