A back-end server acquires viewpoint information representing a position of a virtual viewpoint and a line-of-sight direction from the virtual viewpoint used to generate a virtual viewpoint image based on a plurality of images captured by a plurality of image capturing apparatuses, outputs a first virtual viewpoint image generated using three-dimensional geometric data representing the three-dimensional shape of an object for which the virtual viewpoint image is to be generated if the object is included in an area that is captured by the plurality of image capturing apparatuses, and outputs a second virtual viewpoint image generated without using the three-dimensional geometric data if the object is included in an area that is not captured by a subset of the plurality of image capturing apparatuses.