1. A projection image adjusting system comprising:a storage for storing virtual-environment setting information which indicates in a virtual space created by a computer, a set-up situation of a projection display apparatus set so as to have a desired image state on an object on which an image is projected, and also storing a control set-up value for the projection display apparatus in the desired image state;
a receiving section for receiving real-environment setting information on a set-up situation of the projection display apparatus in a real space; and
a controller for controlling the projection display apparatus in the real space,
wherein, based on the virtual-environment setting information and the real-environment setting information, the controller corrects the control set-up value so as to decrease a difference between an image-projection state in the real space and the desired image state, and based on the corrected control set-up value, the controller controls the projection display apparatus in the real space.