In an endoscope system having a scope unit including image capturing means for observing a subject, and an image processing unit to which at least one scope unit is connectable to be freely attached/detached, the image processing unit includes first data transmission means for transmitting, to the scope unit, a first packet including identification information, and first data reception means for receiving a second packet from the scope unit, and the scope unit includes a nonvolatile memory for storing specific parameters of the scope unit, second data reception means for receiving the first packet from the image processing unit, and second data transmission means for transmitting the second packet to the image processing unit by switching the second packet to a first data format for transferring the specific parameters to the image processing unit or a second data format for transferring realtime information of the scope unit to the image processing unit based on the identification information included in the first packet.
