1. A road map information readout apparatus, said apparatus comprising: a road map information recording medium in which roads included in all or part of areas on a road map are previously classified into a plurality of groups in accordance with types of the roads, different recording formats are respectively assigned to the plurality of groups according to the types of the roads, and connection information of the roads included in each of the groups is recorded in accordance with the recording format assigned to the group; readout range designation means for designating a predetermined readout range; readout control means for reading out from said road map information recording medium the connection information corresponding to the predetermined readout range; and output means for outputting the connection information read out by said readout control means.