In this paper， under the consideration of both local environmental status and transportation network， we
implement Cost Benefit Analysis (CBA) for the southward extension plan of Osaka Monorail Loop-line
by applying a Choice Experiment (CE) method. It is estimated that the benefit cost (B/C) ratio is 1.35 under a
basic scenario. In addition， with a consideration of different kinds of uncertainty in the future， a number
of sensitivity analyses are implemented. The results of sensitivity analysis indicate that the possibility of
generating net benefit is extremely high for the extension plan studied here.