To provide a vehicle-mounted radar system capable of improving object detection performance depending on a situation. The vehicle-mounted radar system includes laser radars 2A to 2D that irradiate the surroundings of a vehicle 1 with a laser beam and receive light reflected by an object around the vehicle 1, and a control device 3 that controls the laser radars 2A to 2D and recognizes an object based on light reception results of the laser radars 2A to 2D. The control device 3 determines whether a laser beam of any of the laser radars 2A to 2D is blocked by the object, and thus an undetected area is created, based on a recognition result of the object. Thus, for example, when the laser beam of the laser radar 2B is blocked by another vehicle 10, and thus an undetected area 11 is created, a detection range of the laser radar 2A adjacent to the laser radar 2B is expanded so that at least a portion of the undetected area 11 is allowed to be detected.