PROBLEM TO BE SOLVED: To provide an image processor for presenting a moving image that appropriately suppresses a shake by setting the strength/weakness of the correction degree of a positional deviation on the basis of operation state information representing a state of an endoscope apparatus, and to provide an endoscope apparatus, a method of operating an image processor, or the like.SOLUTION: The image processor includes an image acquisition part 120 of continuously acquiring reference images by continuous imaging processing by an imaging part of the endoscope apparatus, a state detection part 160 for acquiring operation state information showing an operation state of the endoscope apparatus, and an extraction part 170 for acquiring an extraction image from the reference images, the extraction part 170 extracts the extraction image from the reference images in an extraction mode corresponding to the strength/weakness of a correction degree determined on the basis of the operation state information, the state detection part 160 acquires information on whether the imaging part is in an enlarged observation state as operation state information, and the extraction part 170 weakens the correction degree more when determined to be in an enlarged observation state than when determined not to be in an enlarged observation state according to the information on whether the imaging part is in an enlarged observation state.
