1. A remote instruction system comprising: a controller that controls an image capturing portion to capture an image of a three-dimensional target and transmit a captured image to a remote terminal, and controls a projector that projects an annotation image onto an exterior surface of the three-dimensional target according to an instruction on the captured image given by the remote terminal; and a relative position changing portion that is controlled by the instruction on the captured image given by the remote terminal and changes the position of the target relative to the image projection portion and the image capturing portion.