<p>A projector fixing device for adjusting the fixing state of a projector (8) projecting a video image in a space structure for forming an arbitrary space by coupling one or a plurality of columnar bodies extending upward from the floor with one or a plurality of cross beam bodies (3) extending in the horizontal direction to the floor or by coupling the cross beam bodies (3) with each other. The projector fixing device comprises a fixing means for securing the projector to the cross beam bodies, and a rotary coupling means (82) for coupling the securing means and the projector such that the projector is rotatable in a horizontal plane parallel with the cross beam bodies. Since the projector can project a video image in at least two directions by the rotary coupling means, screen position of the projector can be selected appropriately in the space structure where the projector is installed.</p>
