A translation server connected to a terminal via a network, comprises: an input information controller for receiving a translation instruction sent from the terminal, the translation instruction including location information representing a location of an object document to be translated, source language information representing an source language of the object document and target language information representing a translation target language of the object document, and obtaining the object document to be translated from a Web server on the basis of the location information; an information separator for separating the object document sent from the input information controller into a translation object part and a non-translation object part; a translator for translating the translation object part sent from the information separator according to the source language information and the target language information to obtain a translation result; an information converter for producing a retranslation instruction part for permitting the terminal to display a language information input column for inputting the source language information and the target language information by the user and a retranslation instruction input part and to send the translation instruction including the source language information and the target language information in the language information input column and the location information of the object document to be translated to the translation server; and an information synthesizer for synthesizing the translation result sent from the translator, the retranslation instruction part produced by the information converter and the non-translation object part sent from the information separator and sending a synthesized result to the terminal. As a result, the terminal sends a new translation instruction including the changed language information of the object document to the translation server and operability is effectively improved.