A master encoder obtains in time series one of divided images obtained by dividing an original image into a plurality of sections, obtains identification time for identification of the divided image obtained in time series, and notifies the slave encoder of the identification time, encodes the obtained divided image and generate an encoded divided image, and generates encoding transmission information including in time series encoding information including the encoded divided image and the identification time, and transmits the encoding information. A slave encoder obtains in time series any other than the one of divided image, obtains the identification time set for identification of the divided image from the master encoder, encodes the obtained divided image and generate an encoded divided image, and generates encoding transmission information including in time series encoding information including the encoded divided image and the identification time, and transmit the encoding information.