To provide a communication device which can improve a transmission ability of data without changing a communication line transmission rate prescribed by the specification or the like.

In a communication device on a source side, a single data stream is divided into a plurality of data streams, and each of the divided data streams is respectively transmitted via a different channel, so that the data streams are combined into a single data stream of each channel in a communication device on a sink side. Compared with the prior art of transmitting a data stream only via a single channel, a whole transmission ability can be improved. For example, when a single data stream is divided into N data streams and transmitted via N channels, the transmission rate of the data stream can be made N times the standard rate without broadening the bandwidth of each channel.