An in-vehicle camera calibrator is provided. The in-vehicle camera calibrator includes a targeted camera selector for selecting a targeted camera requiring the calibration, an intermediate camera selector for selecting an intermediate camera which is the in-vehicle camera that intervenes between the targeted camera and a criterial camera, a first calibrator for, when the intermediate camera is not selected, calibrating the targeted camera based on a captured image of an overlapping region between the criterial camera and the targeted camera, and a second calibrator for, when the intermediate camera is selected, calibrating the intermediate camera based on a captured image of an overlapping region between the criterial camera and the targeted camera, and then calibrating the targeted camera based on a captured image between the calibrated intermediate camera and the targeted camera.