1. An imaging apparatus comprising: a circular marker, having two semicircular portions of a first color area and a second color area separated by a center line, which indicates the position and angles for arranging an image of a virtual object in an image of a real space, an image acquiring means for acquiring an image of a real space including the marker, a calculating means for detecting the marker area from the image acquired by the image acquiring means and calculating the position and the angles when arranging a virtual object in the real space based on the marker area, and an imaging means for constructing an image of the virtual object virtually arranged in the real space by the position and angles indicated by the marker based on the calculation results of the calculating means and the shape data of the virtual object.