Mobile terminal receives from a server a content, a sending time information which indicates the time of sending the content, and a time restriction information that indicates the time period when the content can be used. Mobile terminal correlates the content with the sending time information and the time restriction information, and stores them. Mobile terminal calculates the difference between the time of receiving the content and the sending time information. Mobile terminal correlates the difference with the content and stores them. Mobile terminal adds the difference to the current time kept by time keeping unit to obtain a usage determination reference time. Mobile terminal compares the usage determination reference time with the time restriction information to determine whether the mobile terminal can use the content or not.