Travel distance calculation system and travel distance calculation processing device

The problem to be solved by the present invention is to provide a travel distance calculation device and a travel distance calculation processing device that improve user convenience and suppress a decrease in traffic smoothness when providing an accurate travel distance in response to transfer of a vehicle also including a shared automobile. In order to solve the problem, the present invention provides a travel distance calculation system (100) comprising: a user authentication unit (411) that authenticates a user in a vehicle (1) that is a first moving body that can travel by means of energy supply; a travel characteristic information acquisition unit (412) that acquires travel characteristic information when a user uses the vehicle (1) and the vehicle (2); and a travel characteristic control unit (413) that, when a user is authenticated in a vehicle (2) that is a second moving body, calculates a travelable distance on the basis of the travel characteristic information and the vehicle characteristics of the