An endoscope system includes an image pickup portion configured to pick up an image of a subject and output the image as an electrical signal, a processor configured to perform, on the electrical signal, a signal correction that converts the electrical signal into a signal of a video format that is compatible with a signal processed by the image processing apparatus, and an image processing portion configured to perform image processing on the electrical signal after the signal correction. An E/O converter that converts the electrical signal into an optical signal, an optical fiber that transmits the optical signal, and an O/E converter that converts the optical signal into the electrical signal, are arranged in at least one of between the image pickup portion and the processor, and between the processor and the image processing portion.