Abstract: Suitable translations of phrases to be translated in original sentences having a high probability of obtaining natural translated sentences as sentences in a target language from the original sentences in a source language are obtained. A plurality of natural sentences, in the source language composed of a plurality of words, correlated with translated sentences in the target language is registered in corresponding translation database. When a phrase to be translated in natural sentences in the source language is specified, the corresponding translation database is searched for natural sentences containing the phrase to be translated (102). When no natural sentence completely coinciding with the original sentence is found (negative in 104), a degree of coincidence between each of the extracted natural sentences and the original sentence is evaluated, and a translation having the greatest degree of coincidence is displayed (108-112).