A map image and a character string indicating information relating to a spot included on the map image are displayed on a liquid crystal display, in a case where determination is made that a plurality of character strings displayed on the map image overlaps one another with displacement of a display range of the map image, at least one character string is set to non-display to restrain the character strings from overlapping one another, and thereafter, in a case where a state in which the character strings do not overlap one another is returned, and a predetermined time has elapsed or the map image has been rotationally moved at a predetermined angle or more after the character string is set to non-display, the character string is displayed again.