An input unit receives an input sentence in a source language. A translation generating unit generates a translation in a target language with respect to a word included in the input sentence and likelihood of the translation in the target language. A correspondence-information creating unit creates correspondence information, in which the word is associated with the translation. A determining unit determines whether the likelihood generated with respect to the translation in the target language included in the correspondence information is larger than a predetermined threshold value. A learning-data creating unit creates learning data in which a word included in the input sentence is associated with the correspondence information including the translation in the target language having the likelihood larger than the threshold value.