Abstract: The present invention relates to an advertisement information providing system and an advertisement information providing method. According to the present invention, when a data addresser transmits data to a data addressee through a data transmitting server of a network service medium or when the data addressee receives data from the data addresser through a data receiving server of the network service medium, an advertisement matched with the field of interests of which the data addresser and the data addressee are the most interested is generated in real-time and the generated advertisement is transmitted to the data addresser or the data addressee.