To make a mobile robot autonomous, it must have a capability that it investigates a real world and constructs the 3-D environment models. However, the accuracy of a sensor reading mainly depends on the accuracy of image processing system and the alighnment errors of housing. An object position observed in the world also depends on the camera position and attitude from a dead reckoned estimate. So we propose a 3-D model generating system for a mobile robot. In this paper, we consider a rectangular cell whose dimensions are determined from a sensor reading, its accuracy and dispersion with the stereo imaging system. These sensory data are stored in a computer by a list of cells according to a camera position and direction, and a tilt angle. And they are integrated to a rectangular parallelepiped through a convex hull, based on the recorded data and the informations with them. We have examined four typical examples for vehicles and the proposed method proved to be effective to present 3-D models for a mobile robot.