Abstract: A translation support device includes a storage device and a control device. The storage device stores therein an original document file in which original document data is recorded, and a translated document file in which translated document data, representing a translated document translated from an original document represented by the original document data, is recorded. The control device includes a processor, and acts as a detector and a generator, when the processor executes a control program. The detector detects, through comparison between the original document file and the translated document file, a same portion contained in common in both of the files, as an untranslated portion. The generator generates untranslated portion information indicating the untranslated portion.