A driving assistance method of assisting driving of a vehicle, includes, by a computer, acquiring biological information of a driver who is driving the vehicle, acquiring environment information of the driver, acquiring operation information of the driver, generating biological index data from the biological information, generating integrated information by aligning and combining time series of the biological index data, the environment information, and the operation information, calculating accident risk information after a predetermined time, by inputting the integrated information to an accident risk prediction model set in advance, and calculating factor information of the accident risk information by inputting the accident risk information, the integrated information, and accident risk judge information set in advance to a factor calculation model set in advance.