To provide an electronic book provision system that can make advertisements easily recognized by a user. The electronic book acquisition unit (104) acquires an electronic book in which tag is set in the text. The tag indicates a replacement target phrase in the text of the electronic book to be replaced with an advertising phrase on an advertisement. An advertising phrase acquisition unit (106) acquires the stored content of an advertising phrase storage unit (102) storing an advertising phrase such that the advertising phrase is associated with the replacement target phrase or the tags. An advertising phrase insertion unit (108) inserts the advertising phrases into the text of the electronic book based on the tags included in the text of the electronic book and the stored content of the advertising phrase storage unit (102). An output control unit (202) causes an output unit included in a terminal device (20) to output the electronic book in which the advertising phrase has been inserted by the advertising phrase insertion unit (108).