There are provided environmental information detection means (SR) for detecting and storing environmental information around a movable body on the basis of image information output from a specific image capturing means (C1), movable body information detection means (MB) for successively detecting and storing a position and posture of the movable body, information combining means (CB) for combining these information, and correcting a relationship of the position and posture of the movable body relative to the environment to output the information, and obstacle detection means (OD) for detecting an obstacle to bar against movement of the movable body on the basis of the output information. Based on the detected information or the like, a positional relationship between the movable body and the obstacle is determined, then, on the basis of the positional relationship, either one of the information output from the specific image capturing means (C1) and second image capturing means (C2) is selected by display control means (VC), and displayed by display means (VD).