PROBLEM TO BE SOLVED: To provide a mobile vehicle control system capable of changing travelling directions safely in a hazardous area before the mobile vehicle gets too close to down steps.SOLUTION: A mobile vehicle control system includes: a mobile vehicle having an external environment sensor for detecting external environment information and an ID number detection part for detecting an ID number based on received light； an illumination part for illuminating down steps with light including the ID number； a direction calculation part for calculate a direction in which down steps are located adjacent to the mobile vehicle using the external environment information； a control part that controls the travelling of the mobile vehicle and sets the direction where the down steps exist calculated by the direction calculation part as a travel-prohibition range when the ID number detected by the ID number detection part is a predetermined number.
