Abstract: A neighboring object information acquisition device comprises a distance measuring unit measuring a quantity equivalent to a distance to a neighboring object in a predetermined direction. A storage unit stores a sequence of points indicating results of the measurement performed multiple times. An object detection unit detects existence of the object based on the sequence of points. An approximation unit outputs an approximation of the sequence of points by applying a curve or a straight line, so that an approximate curve or an approximate straight line is derived. An evaluation unit outputs a result of evaluation of a reliability of the sequence of points. A determination unit determines object information by selecting one of information derived from the sequence of points and information derived from the result of approximation in accordance with the result of evaluation.