A method for providing wireless communication data for a data gathering system for a mobile object, the method providing the wireless communication data to a wireless communication unit of a device on a mobile object in the data gathering system for a mobile object, the system comprising a ground device installed on the ground and a plurality of devices on a mobile object each of which is installed on a mobile object, each of the devices on a mobile object comprising information storage unit having mobile object information storing means for storing mobile object information including at least one of first mobile object information concerning a mobile object itself on which the device on a mobile object is installed and second mobile object information concerning a device mounted in the mobile object and the wireless communication unit that is mutually connected with the information storage unit by mutually performing cable communication through a cable LAN in accordance with a predetermined cable communication protocol and that performs wireless communication with the ground device through a wireless LAN in accordance with a predetermined wireless communication protocol, wireless communication data configured to perform wireless communication between the ground device and the wireless communication unit and the information storage unit of the device on a mobile object through the wireless LAN in accordance with a predetermined communication protocol by mutually identifying them being set to the wireless communication unit of the device on a mobile object, the ground device being connected with the device on a mobile object through the wireless LAN based on the wireless communication using the set wireless communication data, the mobile object information stored in the mobile object information storing means of the information storage unit being collected by the ground device,
- wherein the wireless communication data that should be set to the wireless communication unit of the device on a mobile object is generated based on prepared data generation information representing the wireless communication data predetermined in association with a mobile object identification code previously provided to the mobile object on which the device on a mobile object is installed to enable identifying the mobile object and the mobile object identification code of the mobile object on which the device on a mobile object to which the wireless communication data should be set is installed, and
- the generated wireless communication data is provided to the wireless communication unit in the device on a mobile object as the wireless communication data that should be set to the wireless communication unit in the device on a mobile object.