A visual travel route indicating apparatus, for use in an automotive vehicle or the like, including a distance sensor for detecting a current distance of travel of the vehicle, a gas rate sensor for detecting a current azimuthal deviation generated by the vehicle during a turning motion, a thermostatic control chamber for enclosing the gas rate sensor hermetically from external temperature fluctuations, and a signal processing unit for arithmetically obtaining a current location plotted on two-dimensional coordinates per a given unit travel distance of the vehicle from the outputs of the two sensors and storing the thus-obtained location data in sequence so as to be read out subsequently for a continuous visual indication of a current locus of the vehicle on a display. The power supply to the thermostatic control chamber is optimally controlled in conjunction with the on/off state of the ignition switch of the vehicle. The visual indication of a current travel route of the vehicle is inhibited until the atmospheric temperature of the thermostatic chamber reaches a desired constant level, whereupon the offset adjustment of the gas rate sensor output is automatically normalized so as to present a precise visual indication of the vehicle's travel route on the display. Further, the occurrence of an abnormal temperature within the atmosphere of the thermostatic control chamber is detected so as to provide a warning to a driver of the vehicle.