An observation system has at least two probes, and each probe has a camera and an illumination light source to illuminate an observation field of the camera. The at least two probes are able to move each other such that, in an observation field of a camera of one probe, an illumination light source of another probe may locate. To avoid disturbances caused by light from the illumination light source of the another probe, and use light from an illumination light source of the one probe to enhance image quality, image capturing by a camera of the one probe is performed within a period in which an illumination light source of the one probe to which the camera belongs is activated and the illumination light source locating in the observation field of the camera is inactivated.