To conduct speech operations by means of speech recognition/speech synthesis without changing a client system in accordance with the service of a center side.

An HTML sentence which matches with service providing contents is generated by an HTML generation processing section 2 by the instruction of a center server 1. Data analysis of the HTML is conducted by an HTML analysis processing section 3. Speech recognition data and speech synthesis data matched with the service are generated by a speech recognition data generating section 4 and a speech synthesis data generating section 5. Interpretation of the received HTML data is conducted by an HTML display processing section 8 of a client system such as an automobile navigation device, a personal computer and a PDA. Speech inputting and outputting are conducted in a user operation section 12 employing the speech recognition and the speech synthesis data so that user's speech operations are made possible. Thus, the service of the center is expanded without changing the client's system.