The purpose of this study is to secure basic data for forecasting demand for new sports public services and to provide basic data on policy strategies for introducing new sports public services. This is achieved by predicting demand for the project using the Bass model, exponential smoothing method, and qualitative Delphi method. First, analysis of the demand for “National Physical Fitness 100” from the Bass model showed that the innovation coefficient was relatively low (0.029) compared to other physical fitness centers and that the initial service spread rate was slow. However, it was found that the imitation coefficient (0.332) was relatively high, the q/p value (11.45) was large, and that demand gradually increased. Secondly, the demand forecast based on the exponential smoothing method appeared more rapidly than in the Bass model. This is because the exponential smoothing method determines an exponential smoothing coefficient, which is an inclination value of the regression line, by the rate of change of existing data. Therefore, stable demand based on the exponential smoothing coefficient can be predicted and used as a basis for the initial demand forecast. Finally, the result predicted by the National Physical Fitness 100 expert Delphi method increased significantly in 2020 but has since become a gentle straight line. This can be interpreted as an expectation for an infrastructure expansion plan such as human resources and facilities, as the national physical fitness budget for 100 operations was to increase in 2020. The Bass model, the exponential smoothing method, and the Delphi method used in the research can thus confirm how the forecast results of the demand for National Physical Fitness 100 are spread by period. This can contribute to the policy decision-making process for efficient government budget management and effectively meeting social needs, as demand by period can be predicted over time from the point of introduction of the service.