An attitude estimation apparatus (30) includes: a data acquiring unit (32) for acquiring observation data; a range-measurement point coordinate calculator (33A) for calculating geodetic coordinates of a range-measurement point in a geodetic coordinate system using positioning data, ranging data, actual attitude data, and an estimated value of an unknown parameter representing an attitude of a flying object; an image coordinate calculator (33B) for calculating coordinates of a projected point by performing projection transformation from the geodetic coordinate system to an image coordinate system on the geodetic coordinates; an image matching processor (34) for detecting image coordinates of the range-measurement point appearing in a first captured image by executing image matching between the first captured image and a second captured image selected from captured images; and an attitude estimator (35) for correcting the estimated value such that a magnitude of a difference between the coordinates of the projected point and the image coordinates decreases.