One of the critical problems in natural language interfaces is the discordance between the expressions covered by the interface and those by the knowledge base. In the graph-based knowledge base such as an ontology, all possible queries can be prepared in advance. As a solution of the discordance problem in natural language interfaces, this paper proposes a method that translates a natural language query into a formal language query such as SPARQL. In this paper, a user query is translated into a formal language by choosing the most appropriate query from the prepared queries. The experimental results show a high accuracy and coverage for the given knowledge base. Author Keywords natural language interface, knowledge base, ontology, knowledge concordance ACM Classification Keywords H.5.2 Information Interfaces and Presentation: User Interfaces—Natural Language General Terms Algorithms, Experimentation