Flights are often delayed due to weather conditions and technical problems, and flight delays may necessitate reassignment of forthcoming flights to gates in real time. Since in many cases, gate reassignment is manually carried out by airport staff, however, it is difficult to improve its effectiveness and efficiency. In this thesis, based on an existing model, we propose a gate reassignment model with a constraint on flight connections and formulate it as 0-1 integer programming problem. Furthermore, we discuss how to generate a gate assignment robust against flight delays. To validate the usefulness of the proposed model, we conducted computational experiments using actual data at Narita International Airport.