In decision making for planning and operating dynamical systems, it is important to predict the future behavior of the systems. However, prediction of the dynamic behavior becomes difficult when uncertainty is included in the system. Therefore, a model that takes into consideration the influence of uncertainty and a decision-making support method using that model are desirable. On the other hand, the Bayesian network is a powerful tool for probabilistic inference and has been used in various fields. In this study, we use the dynamic Bayesian network, which is an application of the Bayesian network, as a model of dynamical systems with uncertainty, and propose a decision-making support method based on the probabilistic inference using the dynamic Bayesian network. The proposed method was applied to a sample process, and its validity was discussed.