Under the development of ubiquitous technologies, people need a novel media system, a multi-sensory media service that satisfies the five senses and gives people a feeling of realism. In order to provide such a service, it is necessary to build knowledge on sensory effects and devices. In this thesis, we propose an ontology-based knowledge model. The proposed ontology model consists of Effect Ontology and Device Ontology. The Effect Ontology represents semantic information regarding multimedia contents and sensory effects synchronized with the contents. The Device Ontology represents semantic information about devices generating sensory effects. We also implemented an application utilizing the proposed ontology model. By using the model, the application can infer sensory effects and their attributes from the predefined semantic information of multimedia contents. We prove the usefulness of our ontology model by showing the results of scenario-based experiments.