The waiting time for patients in outpatient departments of hospitals is a problem throughout the world. In this context, a discrete-event-simulation model was developed to examine congestions and doctor schedules in all departments of an outpatient hospital ward of the Nagoya University hospital. The method of gathering the required data on times for all outpatients and their routes is described in this paper as part of a performing simulation, especially by making use of electronic medical records. This study identified some of the best doctor schedule mixes by integrating the simulation model into an optimization program in order to reduce patient waiting time as well as doctor idle-time without adding a single additional resource.