An apparatus for supervising a vicinity of a vehicle includes: an image capturing unit that captures a plurality of images in which an object is simultaneously captured from different locations; a parallax calculation unit that performs a sub pixel estimation based on the plurality of images to calculate a parallax value; a parallax offset calculation unit that calculates a parallax offset value based on the parallax value under a condition where a decimal part S of the parallax value is within a predetermined range; and a parallax correction unit that corrects the parallax value using the parallax offset value.