PURPOSE: To enable the automatic renewal of a displayed map in accordance with running, by making a cartridge store various informations, and by using these informations for the automatic retrieval of the map and for correction of the detected informations of a geomagnetic sensor.

CONSTITUTION: Informations accompanying the recorded content of a cartridge 11 are stored in ROM 12 and read out by a control section 23. Information on the reducee scale of a map and addresses on a film frame which is called out in a projection window 11c of the catridge 11 are also utilized for calculations. These information are used for the retrieval of the map, and an operation of adjusting the reduced scale of the map projected on a screen 25 with that of a track display by an LCD display 24, and other operations are performed. The informations on the declination and the angle of depression of geomagnetism in the region in the map projected on the screen 25 are also read out from ROM 12, and the correction of the informations of a direction sensor 22 is performed based thereon. Thus, the direction of running can be known accurately on the basis of the detected informations of the sensor 22.