A delivery server includes a content output unit configured to output content, a delivery request reception unit which receives a delivery request transmitted from a client terminal connected to a network, a determination unit which determines whether the content is to be delivered to the client terminal in response to the delivery request when the delivery request is received using the delivery request reception unit, and a transmission unit which transmits the content output from the content output unit to the client terminal when the determination unit determines that the content is to be delivered, and transmit the content output from the content output unit to a booster server connected to the network and further transmit a transfer command including information on the booster server to the client terminal when the determination unit determines that the content is not to be transmitted.