An edge blending device which suppresses an increase in a luminance of a projection screen in an overlap area in which projection lights projected from a plurality of projection units onto a screen overlap each other, is characterized by including: a light shielding unit holder which includes light shielding pattern formation portions which can form a light shielding pattern corresponding to the projection lights forming the overlap area; and a light shielding pattern drive controller which controls a drive of the light shielding unit holder in such a way that the light shielding pattern formation portions are positioned corresponding to the projection lights from the projection units.