A content delivery system comprising: a content delivery server; and a content delivery client, wherein the content delivery client comprises: a first wireless communication circuitry adapted to perform first wireless communication; a second wireless communication circuitry adapted to perform second wireless the communication, the speed of the second wireless communication being higher than the speed of the first wireless communication, the area of the second wireless communication being narrower than the area of the first wireless communication; and a first storage, the content delivery server comprises: a third wireless communication circuitry adapted to perform the first wireless communication; a fourth wireless communication circuitry adapted to perform the second wireless communication; and a second storage having a larger capacity than a capacity of the first storage, the content delivery client receives a contents list including information on each of one or more first contents from the content delivery server though the first wireless communication circuitry and selects the desired content from said contents list, list, the content delivery client detects the area of the second wireless communication using the second wireless communication circuitry, when free space of the first storage is smaller than a total volume of the one or more first contents selected from the contents list, the content delivery client uploads one or more second contents stored in the first storage to the content delivery server through the second wireless communication circuitry and then downloads the one or more first contents, the content delivery server transmits the contents list to the content delivery client through the third wireless communication circuitry, the content delivery server detects the area of the second wireless communication using the fourth wireless communication circuitry, and when the one or more second contents are uploaded from the content delivery client, the content delivery server temporarily stores the one or more second contents in the second storage and then downloads the one or more first contents selected to the content delivery client through the fourth wireless communication circuitry. a content delivery server; and a content delivery client, wherein the content delivery client comprises: a first wireless communication circuitry adapted to perform first wireless communication; a second wireless communication circuitry adapted to perform second wireless the communication, the speed of the second wireless communication being higher than the speed of the first wireless communication, the area of the second wireless communication being narrower than the area of the first wireless communication; and a first storage, a first wireless communication circuitry adapted to perform first wireless communication; a second wireless communication circuitry adapted to perform second wireless the communication, the speed of the second wireless communication being higher than the speed of the first wireless communication, the area of the second wireless communication being narrower than the area of the first wireless communication; and a first storage, the content delivery server comprises: a third wireless communication circuitry adapted to perform the first wireless communication; a fourth wireless communication circuitry adapted to perform the second wireless communication; and a second storage having a larger capacity than a capacity of the first storage, the content delivery client receives a contents list including information on each of one or more first contents from the content delivery server though the first wireless communication circuitry and selects the desired content from said contents list, list, the content delivery client detects the area of the second wireless communication using the second wireless communication circuitry, a third wireless communication circuitry adapted to perform the first wireless communication; a fourth wireless communication circuitry adapted to perform the second wireless communication; and a second storage having a larger capacity than a capacity of the first storage, the content delivery client receives a contents list including information on each of one or more first contents from the content delivery server though the first wireless communication circuitry and selects the desired content from said contents list, list, the content delivery client detects the area of the second wireless communication using the second wireless communication circuitry, when free space of the first storage is smaller than a total volume of the one or more first contents selected from the contents list, the content delivery client uploads one or more second contents stored in the first storage to the content delivery server through the second wireless communication circuitry and then downloads the one or more first contents, the content delivery server transmits the contents list to the content delivery client through the third wireless communication circuitry, the content delivery server detects the area of the second wireless communication using the fourth wireless communication circuitry, and when the one or more second contents are uploaded from the content delivery client, the content delivery server temporarily stores the one or more second contents in the second storage and then downloads the one or more first contents selected to the content delivery client through the fourth wireless communication circuitry.