A projection device includes at least one projection module and at least one adjusting structure. The projection module has an optical axis and is adapted to emit an image beam. The image beam is transmitted to a projection target to form a projection image. The adjusting structure includes a base and an adjusting component. The adjusting component is rotatably connected to the base along a first axis, and the projection module is rotatably connected to the adjusting component along the optical axis. The adjusting component and the projection module are adapted to rotate along the first axis such that the projection image moves vertically, and the projection module is adapted to rotate along the optical axis such that the projection image rotates.