To provide a translation system using a plurality of machine translation systems capable of selecting the best translation with the highest precision.

This method for selecting the best translation comprises a step (92) for calculating a score group for each translation result by applying a translation model, a language model, and a score function using the both models to each translation result, steps (94, 96) for executing a statistical test to the score group, and for deciding whether or not there is any score group with any significant difference with another score group, and steps (98, 100) for selecting the best translation from among the plurality of translation results according to the decision result. The decision step may be configured to estimates the score of each translation result by using a preliminarily learnt regression tree based on human evaluation and scoring functions.