10. The machine translation device according to claim 1 , wherein the syntax analysis part produces a syntax parse tree by analyzing syntax of the caption sentence based on the domain-specific word co-occurrence dictionary for structure analysis, when a sentence pattern applicable to the caption sentence does not exist.
10. The machine translation device according to claim 1 , wherein the syntax analysis part produces a syntax parse tree by analyzing syntax of the caption sentence based on the domain-specific word co-occurrence dictionary for structure analysis, when a sentence pattern applicable to the caption sentence does not exist. 11. The machine translation device according to claim 10 , wherein a knowledge format of the domain-specific word co-occurrence dictionary for structure analysis is {preceding part-of-speech (POS)1_followingPOS2_preceding part of last word1_following part of last word2 frequency1 <domain1> frequency2 <domain2> . . . frequency n <domain n>}.