1. A distance information estimating apparatus comprising: an acquiring unit configured to acquire image data and resolution-converted image data, the resolution-converted image data being obtained by converting a resolution of the image data; a distance information estimating unit configured to estimate distance information of an image represented by the image data and distance information of a resolution-converted image represented by the resolution-converted image data; and a distance information combining unit configured to combine the distance information of the image and the distance information of the resolution-converted image.