Provided is a content delivery system in which a content delivery server delivers content to a content delivery client. The content delivery client transmits content using first wireless communication, detects the area of second wireless communication, and if it determines that sufficient free space is not present in a first storage thereof, transmits a part of data stored in the first storage to the content delivery server using the second wireless communication. The content delivery server makes free space in the first storage by temporarily storing the data in a second storage thereof and then delivers content using the second wireless communication on the basis of the control information.