There is provided a communication device which communicates with a target communication device, including: a communication controller, a general-purpose processing unit, a data transfer processing unit and a starting unit. The general-purpose processing unit communicates with the target communication device via the communication controller. The data transfer processing unit receives data from the target communication device via the communication controller. The starting unit starts up the data transfer processing unit. The general-purpose processing unit receives a data transfer start request from the target communication device. The starting unit starts up the data transfer processing unit when the general-purpose processing unit receives the data transfer start request. The general-purpose processing unit or the data transfer processing unit notifies a data transfer start response to the target communication device after the data transfer processing unit is started up.