A recording system for preventing inconsistencies between the time information of the AV data which is recorded on the recording medium of the image sensing device (camera integrated digital video recorder and so on), and the time information of the AV data which is recorded on the recording medium of an external recording device. The image sensing device determines whether or not the AV data is recorded on its recording medium when the AV data is digitally output. If it is recorded, the AV data is digitally output with adding change-prohibited information. The external recording device determines whether or not the change-prohibited information is added to the AV data which has been digitally input. If the change-prohibited information is added, the AV data is recorded to a recording medium without changing the time information of the AV data.