An advertisement inserted in contents of, for example, a game does not serve its purpose after a while. An advertisement-information reception unit (112) receives an advertisement-space definition file (32). The advertisement-space definition file (32) is a file that defines an advertisement space for an advertisement to be inserted when contents are displayed and an advertising agency is assigned to the advertisement space. An assignment changing unit (116) cancels the assignment of an advertising agency, whose license has expired, to the advertisement space even when the advertising agency is assigned to the advertising space in the advertisement-space definition file (32). An advertisement downloading unit (118) downloads advertisement data to be inserted in the advertisement space from the server of the advertising agency validly assigned to the advertisement space. A rendering engine (130) inserts, when displaying the contents on a screen, the downloaded advertisement in the advertisement space and displays accordingly.