A route guidance apparatus comprising: a location information obtainer configured to obtain location information regarding a current location of a pre-registered route guidance apparatus, denoted subject apparatus; a communication controller configured to transmit the location information of the subject apparatus obtained by the location information obtainer to another pre-registered route guidance apparatus, and configured to receive the location information of the another pre-registered route guidance apparatus, wherein the subject apparatus and the another pre-registered route guidance apparatus are pre-registered to each other; and a function selector configured to enable the communication controller to transmit to the another pre-registered route guidance apparatus heading direction information indicating the heading direction when the subject apparatus is the main device, and enables the communication controller to receive the heading direction information from the another pre-registered route guidance apparatus determined to be the main device when the subject apparatus is a sub device characterized in that the route guidance apparatus further comprises a location relationship determiner configured to determine whether the subject apparatus precedes the another pre-registered route guidance apparatus in a heading direction, based on a location relationship of the subject apparatus and the another pre-registered route guidance apparatus with respect to the heading direction of the subject apparatus when the subject apparatus and the another apparatus move in same heading direction; wherein the heading direction is based on a progress at a predetermined time of current location information, and the location relationship is determined according to the location information of the subject apparatus obtained by the location information obtainer and the location information of the another pre-registered route guidance apparatus obtained by the communication controller; an operation mode determiner configured to operate the subject apparatus as a main device when the location relationship determiner determines that the subject apparatus precedes the another pre-registered route guidance apparatus in the heading direction, and configured to operate the subject apparatus as a sub device when the location relationship determiner determines that the subject apparatus does not precede the another pre-registered route guidance apparatus in the heading direction. a location information obtainer configured to obtain location information regarding a current location of a pre-registered route guidance apparatus, denoted subject apparatus; a communication controller configured to transmit the location information of the subject apparatus obtained by the location information obtainer to another pre-registered route guidance apparatus, and configured to receive the location information of the another pre-registered route guidance apparatus, wherein the subject apparatus and the another pre-registered route guidance apparatus are pre-registered to each other; and a function selector configured to enable the communication controller to transmit to the another pre-registered route guidance apparatus heading direction information indicating the heading direction when the subject apparatus is the main device, and enables the communication controller to receive the heading direction information from the another pre-registered route guidance apparatus determined to be the main device when the subject apparatus is a sub device the route guidance apparatus further comprises a location relationship determiner configured to determine whether the subject apparatus precedes the another pre-registered route guidance apparatus in a heading direction, based on a location relationship of the subject apparatus and the another pre-registered route guidance apparatus with respect to the heading direction of the subject apparatus when the subject apparatus and the another apparatus move in same heading direction; wherein the heading direction is based on a progress at a predetermined time of current location information, and the location relationship is determined according to the location information of the subject apparatus obtained by the location information obtainer and the location information of the another pre-registered route guidance apparatus obtained by the communication controller; an operation mode determiner configured to operate the subject apparatus as a main device when the location relationship determiner determines that the subject apparatus precedes the another pre-registered route guidance apparatus in the heading direction, and configured to operate the subject apparatus as a sub device when the location relationship determiner determines that the subject apparatus does not precede the another pre-registered route guidance apparatus in the heading direction.