A projection system includes a projection unit configured to project a projected image on a surface for projection; an image capturing unit configured to capture an image of an image-capturing area representing an area; an operation detection unit configured to detect any user operation on an operation target image representing a targeted image for the user operation by using the captured image; a calculation unit configured to calculate image-capturing area coordinates for specifying a position of the image-capturing area in the projected image based on the captured image and the projected image; a position determination unit configured to determine a position of the operation target image in the projected image based on the image-capturing area coordinates; and a projected image generating unit configured to generate a projected image in which the operation target image is laid out on the determined position.