A transportation demand-and-supply matching system, comprising: a storage device that is configured to store information on each of travel demand and transportation supply capability in a predetermined area; and an arithmetic device that is configured to estimate whether a congested route in the area is congested and to identify a congested-route transportation vehicle on the congested route based on the information on each of the travel demand and the transportation supply capability; to estimate an avoidance route for avoiding the congested route, and a provisional transportation vehicle which may be operated on the avoidance route in the area by a predetermined algorithm; and to output information on each of the avoidance route and the provisional transportation vehicle to a predetermined device; characterized in that the arithmetic device is further configured to perform processing of notifying a terminal of each of passengers of the congested route of a request for checking presence or absence of utilization desire regarding the avoidance route and the provisional transportation vehicle, wherein every time a reply indicating presence of utilization desire of the passenger is obtained from the terminal, to increment a predetermined value which is based on a degree of the utilization desire from the passenger and which indicates feasibility of the avoidance route and the provisional transportation vehicle, and to notify at least one of the terminal of the passenger and a terminal of an entity who schedules an operation of the provisional transportation vehicle, of information on the predetermined value. a storage device that is configured to store information on each of travel demand and transportation supply capability in a predetermined area; and an arithmetic device that is configured to estimate whether a congested route in the area is congested and to identify a congested-route transportation vehicle on the congested route based on the information on each of the travel demand and the transportation supply capability; to estimate an avoidance route for avoiding the congested route, and a provisional transportation vehicle which may be operated on the avoidance route in the area by a predetermined algorithm; and to output information on each of the avoidance route and the provisional transportation vehicle to a predetermined device; characterized in that the arithmetic device is further configured to perform processing of notifying a terminal of each of passengers of the congested route of a request for checking presence or absence of utilization desire regarding the avoidance route and the provisional transportation vehicle, wherein every time a reply indicating presence of utilization desire of the passenger is obtained from the terminal, to increment a predetermined value which is based on a degree of the utilization desire from the passenger and which indicates feasibility of the avoidance route and the provisional transportation vehicle, and to notify at least one of the terminal of the passenger and a terminal of an entity who schedules an operation of the provisional transportation vehicle, of information on the predetermined value.