PURPOSE: To reduce the post-editing load by performing the translation processing while keeping the interim findings including the assurance after selecting a branch point of a rule application tree.

CONSTITUTION: A control part 12 sends a translation subject sentence inputted through an input part 11 to a translation part 14 and also consulting a branch point table 13 to take out the interim findings kept at a translation starting branch point out of an interim findings store part 15 with a display instruction of the next candidate sentence used as a key. Then the interim findings are sent to the part 14. At the part 14 the translation is carried out with application of the translation processing rules for analysis and generation and a branch having the highest assurance is selected at a branch point for procession of the translation processing. The branches of a rule application tree having the assurance higher than a prescribed level where the rules shown by each branch are satisfied are kept as they are. Then the interim findings including the assurance of the kept branches are stored in the part 15. Thus the next candidate of a translated sentence can be outputted while evading the explosion of a solution. As a result, the post-editing load is reduced.