A projection system includes a visible light projector, a camera and an image processor. The visible light projector projects an image with visible light onto the object. The camera captures an image of the object and has an optical axis not coinciding with an optical axis of the visible light projector. The image processor generates an image to be projected with visible light onto the object based on the image captured by the camera. The image processor includes a corrector and an image generator. The corrector corrects a deviation between a projection image and the object. The corrector is configured to calculate a projection region on the object onto which an image is projected by the visible light projector. The image generator is configured to generate image data to project the image to be projected onto the object onto the projection region.