In order to provide a vehicle behavior prediction device and a vehicle behavior prediction method, and a driving assistance device that uses said vehicle behavior prediction device, which enables vehicle behavior to be predicted in a highly accurate manner, a vehicle control device is installed in a vehicle. This vehicle control device is provided with a distribution calculation unit and a vehicle behavior prediction unit. The distribution calculation unit determines, on the basis of driving condition information that has been collected, probability distributions for when deceleration behavior occurs and does not occur. The vehicle behavior prediction unit determines the relative positional relationships between the driving speed and acceleration of vehicles ahead with respect to the probability distributions, and, on the basis of the relative positional relationships that have been determined, predicts the behavior of a vehicle that is subject to prediction.