1. A translation system comprising: an image reading unit that optically reads an image of a manuscript and generates image data; an inputting unit that inputs a translation target language; a character recognizing unit that generates an original text by performing a character recognition process on the image data generated by the image reading unit; a translation database that stores translation phrases in a plurality of languages, language identifiers that specify the language in which each individual translation phrase is written, and document identifiers that identify a content of the translation phrase regardless of the language in which the translation phrase is written; an extracting unit that extracts the document identifier which specifies the content of the original text from the original text; a searching unit that searches the translation database for a translation text associated with a document identifier identical to the document identifier extracted from the original text by the extracting unit and a language identifier identical to the language identifier which specify the translation target language input by the inputting unit; and an outputting unit that outputs the translation text searched by the searching unit wherein if the translation text associated with the document identifier is not found in the translation database, the original text is translated to generate a translation text for the original text and the language identifier, the document identifier, and the generated translation text are automatically stored in the translation database.