1. An environment recognizing device to be used by a traveling type robot in an environment containing one or more than one obstacles in order to recognize the environment, the device comprising: plane detecting means for computing a plane parameter on the basis of input images and detecting a plane on the basis of the plane parameter; obstacle recognizing means for recognizing an obstacle, if any, on the plane detected by the plane detecting means; and environment map updating means for drawing an environment map and/or update the existing environment map on the basis of information on the obstacle recognized by the obstacle recognizing means; the plane detecting means being adapted to detect a group of planes including a reference plane to be used as reference and one or more than one other planes substantially parallel to the reference plane; the environment map updating means being adapted to draw an environment map and/or update the existing environment map for the plane carrying an obstacle as recognized by the obstacle recognizing means out of the group of planes.