A calibration target detection apparatus comprising: a light measurement region setting unit for setting a long light measurement region having a shape corresponding to a rectangle having a first side and a second side, the first side being longer than the second side; a detection unit for detecting light measurement information of the long light measurement region with the use of a photometer provided to an onboard camera; a profile generation unit for generating a first profile, wherein in the first profile, when the first side of the long light measurement region corresponds to a predetermined first direction and the long light measurement region is scanned along a calibration target in a second direction orthogonal to the first direction, the change in the light measurement information in the second direction is shown; and for generating a second profile, wherein in the second profile, when the first side of the long light measurement region corresponds to the second direction and the long light measurement region is scanned along the calibration target in the first direction, the change in the light measurement information in the first direction is shown; and a position calculation unit for calculating, on the basis of a characteristic point (P H, P V, P 1, P 2, P 3, P 4) of the first and second profiles associated with the calibration target, a position of the calibration target or a position of a predetermined location of the calibration target, the calibration target being used for calibrating the onboard camera, and the calibration target being included in a captured image acquired by the onboard camera. a light measurement region setting unit for setting a long light measurement region having a shape corresponding to a rectangle having a first side and a second side, the first side being longer than the second side; a detection unit for detecting light measurement information of the long light measurement region with the use of a photometer provided to an onboard camera; a profile generation unit for generating a first profile, wherein in the first profile, when the first side of the long light measurement region corresponds to a predetermined first direction and the long light measurement region is scanned along a calibration target in a second direction orthogonal to the first direction, the change in the light measurement information in the second direction is shown; and for generating a second profile, wherein in the second profile, when the first side of the long light measurement region corresponds to the second direction and the long light measurement region is scanned along the calibration target in the first direction, the change in the light measurement information in the first direction is shown; and a position calculation unit for calculating, on the basis of a characteristic point (P H, P V, P 1, P 2, P 3, P 4) of the first and second profiles associated with the calibration target, a position of the calibration target or a position of a predetermined location of the calibration target, the calibration target being used for calibrating the onboard camera, and the calibration target being included in a captured image acquired by the onboard camera.