A projector including a light source, a light valve, a projection lens and a displacement module is provided. The light source generates an illumination light. The light valve converts the illumination light into a multi-pixel area image light. The projection lens is disposed in a transmission path of the multi-pixel area image light. The image displacement module includes a carrier, an optical element, a frame and a base. The carrier, the frame and the base are substantially coplanar with each other, and the multi-pixel area image light provided is configured to be moved by the optical element and being moved along a third direction in response to the spinning of the carrier, and the first direction is different from the second direction. Furthermore, a three-dimensional printing apparatus is also provided.