The present invention relates to an on-board camera, comprising a rear housing, a front housing, a lens mounted in the front housing and a sensor fixed on the rear housing; and its manufacturing method. The rear housing is welded to the front housing via a laser to form a seal cavity between the two housings to accommodate the lens and the sensor, and the focal length of the lens is adjusted by adjusting the distance between the sensor and the lens which is further adjusted by the welding height of the two housings.