This research proposes a method for analyzing demand of sightseeing trips to evaluate road network improvement projects. A model system of describing behavior of single-day sightseeing travel by auto is developed. The system consists of the scheduling model and the destinationroute choice model using the method of disaggregate discrete choice analysis. The model are estimated from questionnaire survey data on holiday trips. Using the proposed model system, we conducted demand forecasting for alternative improvement project on the road network.