12. The machine translation apparatus according to claim 11 , wherein if the original word is arranged and associated with a second original word, the translation word selection means creates a plurality of combinations using each of the translation word candidates from the original word and from the second original word, and selects one of the combinations from the list including the compound word of the target language document database.
11. The machine translation apparatus according to claim 9 , wherein the translation word learning means includes: a translation word candidate memory which stores the plurality of translation word candidates of the original word; an evaluation basis selection means for storing an evaluation basis for selecting the translation word; a non-applied word of translation word's selection memory which stores the non-applied word of translation word's selection; and a translation word selection means for selecting the translation word from the plurality of translation word candidates by using at least one of the target language document databases, the evaluation basis and the non-applied word of translation word's selection.