A display system comprising: an irradiator configured to irradiate an object with excitation light having a predetermined wavelength to cause a photosensitive substance to emit fluorescence; an imager configured to capture a capture image and a visible light image of the object, the capture image based on light excited by the excitation light, and the visible light image based on light in a visible light region; a projection control device configured to generate a projection image (6, 6', 6") based on the capture image, a display control device configured to generate a display image based on the capture image captured by the imager; a projector configured to project the projection image (6, 6', 6") onto the object; a display configured to display a superimposed image synthesized by the display control device from the capture image, the visible light image and the projection image (6, 6', 6") in a superimposed manner with each other; and an adjuster configured to adjust the projection image (6, 6', 6") on the display, based on a user operation, characterized in that the display system has a normal mode that is an operation mode for performing a projecting operation, and an adjustment mode that is an operation mode for adjusting setting related to the projection image (6, 6', 6") generated based on the capture image during execution of the normal mode, wherein during the adjustment mode, the display is configured to display the projection image (6, 6', 6") with the setting being adjustable by the adjuster, and during the normal mode, the projector is configured to project the projection image (6, 6', 6") in accordance with the setting adjusted by the adjuster during the adjustment mode. an irradiator configured to irradiate an object with excitation light having a predetermined wavelength to cause a photosensitive substance to emit fluorescence; an imager configured to capture a capture image and a visible light image of the object, the capture image based on light excited by the excitation light, and the visible light image based on light in a visible light region; a projection control device configured to generate a projection image (6, 6', 6") based on the capture image, a display control device configured to generate a display image based on the capture image captured by the imager; a projector configured to project the projection image (6, 6', 6") onto the object; a display configured to display a superimposed image synthesized by the display control device from the capture image, the visible light image and the projection image (6, 6', 6") in a superimposed manner with each other; and an adjuster configured to adjust the projection image (6, 6', 6") on the display, based on a user operation, characterized in that the display system has a normal mode that is an operation mode for performing a projecting operation, and an adjustment mode that is an operation mode for adjusting setting related to the projection image (6, 6', 6") generated based on the capture image during execution of the normal mode, wherein during the adjustment mode, the display is configured to display the projection image (6, 6', 6") with the setting being adjustable by the adjuster, and during the normal mode, the projector is configured to project the projection image (6, 6', 6") in accordance with the setting adjusted by the adjuster during the adjustment mode.