A camera system includes a detection unit that detects fitting errors of a camera as displacement quantities in a first direction, a second direction and an optical axis rotating direction of an image picked up by the camera, a selection unit that selects a rotation correcting quantity corresponding to the displacement quantity in the optical axis rotating direction from plural rotation correction maps prepared in advance, a computation unit that computes the correcting quantities in the first direction and the second direction respectively based on the detected displacement quantities in the first direction and the second direction using linear equations; and a correction unit that corrects the displacements in the first direction, the second direction and the optical axis rotating direction of the picked up image based on the selected rotation correcting quantity and the computed correcting quantities in the first direction and the second direction.