A positioning apparatus (12, 12B) comprising: a first calculator that calculates a first position and a first attitude of a moving body indicating a relative position and a relative attitude of the moving body with respect to a reference position and a reference attitude, based on a plurality of images captured by an image capturing apparatus mounted on the moving body; a storage apparatus that stores information on identifiers, positions, and attitudes of a plurality of markers disposed at predetermined positions and visually distinguishable from each other, and information on a map containing a passageway for the moving body; a second calculator that calculates a second position and a second attitude of the moving body indicating a position and an attitude of the moving body in the map; and a corrector that corrects the first position and the first attitude based on the second position and the second attitude to generate a third position and a third attitude of the moving body, characterized in that the second calculator extracts one of the plurality of markers from an image captured by the image capturing apparatus and calculates the second position and the second attitude of the moving body based on a position and an attitude of the one extracted marker, and calculates an angle of a direction of the moving body with respect to a normal line to a plane of the one marker, based on a position and an attitude of the moving body in a marker coordinate system with an origin at the one marker; and wherein, when the calculated angle is not larger than a first threshold, the corrector does not correct the first position and the first attitude based on the second position and the second attitude, and generates the first position and the first attitude as the third position and the third attitude, when the calculated angle is larger than the first threshold, the corrector corrects the first position and the first attitude based on the second position and the second attitude to generate the third position and the third attitude. a first calculator that calculates a first position and a first attitude of a moving body indicating a relative position and a relative attitude of the moving body with respect to a reference position and a reference attitude, based on a plurality of images captured by an image capturing apparatus mounted on the moving body; a storage apparatus that stores information on identifiers, positions, and attitudes of a plurality of markers disposed at predetermined positions and visually distinguishable from each other, and information on a map containing a passageway for the moving body; a second calculator that calculates a second position and a second attitude of the moving body indicating a position and an attitude of the moving body in the map; and a corrector that corrects the first position and the first attitude based on the second position and the second attitude to generate a third position and a third attitude of the moving body, characterized in that the second calculator extracts one of the plurality of markers from an image captured by the image capturing apparatus and calculates the second position and the second attitude of the moving body based on a position and an attitude of the one extracted marker, and calculates an angle of a direction of the moving body with respect to a normal line to a plane of the one marker, based on a position and an attitude of the moving body in a marker coordinate system with an origin at the one marker; and wherein, when the calculated angle is not larger than a first threshold, the corrector does not correct the first position and the first attitude based on the second position and the second attitude, and generates the first position and the first attitude as the third position and the third attitude, when the calculated angle is larger than the first threshold, the corrector corrects the first position and the first attitude based on the second position and the second attitude to generate the third position and the third attitude.