Preferences of each user are more accurately grasped from a playback history of a playback type content such as music and video and advertisement information that reflects preferences per user is served. Each mobile terminal transmits content playback history information which is a playback history of a content played back on each mobile terminal to an advertisement server, the advertisement server summarizes the content playback history information from each mobile terminal, creates a summary list or playback content list, determines preferences for content of the mobile terminal user from the content playback history information of the mobile terminal to which an advertisement is to be served, compares the determined preference information with the summary list, extracts a content that matches the preferences of the mobile terminal user from the summary list, creates content-related advertisement information extracted from the summary list and serves the advertisement information to the mobile terminal user.