An information processor includes: a similarity data generation portion generating similarity data that represents the calculated similarity to the image in the reference block in association with a position within the search range; a result evaluation portion detecting a position with a maximum similarity value for each piece of the similarity data and screening the detection result by making a given evaluation of the similarity; a depth image generation portion finding a parallax for each of the reference blocks using the detection result validated as a result of screening, calculating a position of a subject in a depth direction on a basis of the parallax, and generating a depth image by associating the position of the subject in the depth direction with an image plane; and an output information generation section performing given information processing on a basis of the subject position in a three-dimensional space using the depth image and outputting the result of information processing.