1. A voice chat system, comprising: a plurality of information processing apparatuses that perform a voice chat while performing speech recognition; and a search server connected to the plural information processing apparatuses via a communication network, wherein the search server discloses a search keyword list containing the search keywords searched by the search server and rank information associated with the search keyword list to at least one of the information processing apparatuses, the at least one information processing apparatus comprising: a recognition word dictionary generating unit that acquires the search keyword list from the search server to generate a recognition word dictionary containing words for use in the speech recognition; a speech recognition unit that performs speech recognition on voice data obtained from a dialog of the conversation during the voice chat by referencing a recognition database containing the recognition word dictionary; a voice conversation control unit that performs communication control of the voice data with at least one information processing apparatus; and a keyword detection unit that detects keywords related to the content of the conversation during the voice chat from the result of the speech recognition, wherein the search server represents a website that provides a keyword search service and a directory search service so that a user uses the search server to search for information available through Internet.