To provide a taxi reservation system and its method and program capable of enhancing ride ratio of a taxi and efficiently allocating an vacant taxi.

The taxi reservation system has a customer terminal 4 for transmitting a taxi reservation application information for representing a taxi reservation application of a customer, a customer desired term information for representing desired term information of the customer at the time of riding the taxi and a customer location information for representing current location of the customer, an on-board terminal 6 for transmitting a driver desired term information for representing desired terms of the driver to take a customer on the taxi and a current location of the taxi, a center server 2 for receiving the taxi reservation application information from the customer terminal, a customer desired term information and a customer current location information, and for selecting a vacant taxi of which desired terms of the driver matches the customer to the on-board terminal.