A keyword advertising service method for providing search information in response to a search request, the method includes the steps of: maintaining a search information database for storing at least one search information record; receiving a search request packet including a keyword inputted in a partner site selected by a user and a site identifier for identifying the partner site, from the partner site; extracting, in response to the search request packet, at least one search information record including a keyword corresponding to the keyword included in the search request packet, from the search information database, by using the bidding participation fee; rolling the extracted search information records independently from the bidding participation fee to be displayed on a result list field and providing the result list field to the partner site in response to the search request; and charging an advertiser corresponding to the search information record, in the case the user clicks the search information record in the search result field.