PROBLEM TO BE SOLVED: To provide an optical-scanning observation system capable of easily executing work for making a field angle of an image acquired by actually scanning a subject into an appropriate field angle.SOLUTION: An optical-scanning observation system includes an endoscope for scanning a subject by illumination light emitted from a light source part and receiving return light, a driving signal generation part for generating a driving signal for scanning the subject by a predetermined scanning route and outputting it to the endoscope, an image generation part for generating an image according to the return light, an operation part for acquiring an observation distance and a scanning distance based on a test chart image generated when a predetermined test chart is scanned as a subject, and calculating a field angle of the endoscope using the acquired observation distance and the scanning distance, and a control part for executing control to change an amplitude of the driving signal to cause the field angle calculated by the operation part to coincide with a predetermined field angle.SELECTED DRAWING: Figure 1
