1. A monitor system of a vehicle outside, comprising: image-measured distance detecting means for detecting a distance between a vehicle and a three-dimensional object existing in front of the vehicle based on informations of an image in front of the vehicle; laser-measured distance detecting means for detecting the distance between the vehicle and the three-dimensional object existing in front of the vehicle on the basis of the information of a laser radar by projecting a laser beam from the vehicle; three-dimensional object recognizing means for recognizing the three-dimensional object existing in front of the vehicle based on the distance detected by the image-measured distance detecting means and the distance detected by the laser-measured distance detecting means; and distance detecting capability diagnosing means for determining a deterioration of a distance detecting capability of the image-measured distance detecting means based on the distance of the three-dimensional object as well as determining the deterioration of a distance detecting capability of the laser-measured distance detecting means based on the distance.