An endoscope system includes: an image pickup apparatus in which an insertion portion is detachable, the image pickup apparatus picking up an optical image of light from an observed object a focus changing section that can change focus of the image pickup apparatus a control section that generates a control signal to control the optical image in a focused state in a state in which the insertion portion is fitted to the image pickup apparatus a storage section that stores data associating a type of the insertion portion and control information an identification section that reads a predetermined code to identify the type of the insertion portion and an optical characteristic acquiring section that acquires the control information corresponding to the type of the insertion portion identified by the identification section to acquire an optical characteristic of the insertion portion used to generate the control signal.
