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 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.