This paper describes a system for supporting development of ontology in a distributed manner. By a distributed manner, we mean ontology is divided into several component ontologies, which are developed by different developers in a distributed environment. The target ontology is obtained by com-piling the component ontologies. These component ontologies are identified ac-cording to their conceptual level or domain characteristics. The distributed development of ontologies applies to many situations such as cooperative development, reusing ontologies and so on. To support such a way of ontology development, we investigate the dependency between component ontologies and design some functions for management of these ontologies based on their dependencies. We next consider the influence of a change of one ontology to others through its dependencies and design a function to suggest a few candidate modifications of the influenced ontology for keeping the consistency. We also present some examples of how the system works.