In this paper, we design and implement a system for managing domain specific thesauri, where object-oriented paradigm is applied to thesaurus construction, concept browsing and query-based reference. This system provides an objected-oriented mechanism to assist domain experts in constructing thesauri; it determines a considerable part of relationship degrees between terms by inheritance and supplies domain experts with information available from a thesaurus being constructed This information is especially useful to enforce consistency between the hierarchies of a thesaurus, each constructed by different experts in different sites through cooperation. It may minimize the burden of domain eIn this paper, we design and implement a system for managing domain specific thesauri, where object oriented paradigm is applied to thesaurus construction, concept browsing and query based reference. This system provides an objected mechanism to assist domain experts in constructing thesauri: it determines a considerable part of relationship degrees between terms by inheritance and supplies domain experts with information available from a thesaurus being constructed. This information is especially useful to enforce consistency between the hierarchies of a thesaurus, each constructed by different experts in different sites through cooperation. It may minimize the burden of domain experts caused from the exhaustive specification of individual relationship. This system also provides an abstracted browsing and a query based reference, which allow users to easily verify thesaurus terms before they are used in usual boolean queries. The verification is made by actively searching for them in the thesaurus. Reference queries and abstracted browsing views facilitate this searching. The facility is indispensable especially when precision counts for much.