A projection system includes an invisible light projector, a background member, an imaging unit, an image generator, and a visible light projector. The invisible light projector projects a predetermined invisible light image onto the object via invisible light. The background member is disposed behind the object in a direction of the invisible light emitted from the invisible light projector. The imaging unit captures an image of the invisible light projected from the invisible light projector. The image generator measures a shape of the object based on the image captured by the imaging unit to generate image data showing image content for projection onto the object in accordance with the measured shape. The visible light projector projects the image content shown by the image data onto the object via visible light. The background member has a light shielding surface that does not diffusely reflect the invisible light incident thereon.