A driving assistance system includes a history storage unit, a behavior detecting unit, a state determining unit, and a notifying unit. The history storage unit stores a behavior history which is a past behavior history of a driver. The behavior detecting unit detects a current behavior of the driver. The state determining unit determines an unsafe state by comparing the transition of the behavior detected by the behavior detecting unit with the behavior history of the driver corresponding to a current driving path. If the state determining unit determines the unsafe state, the notifying unit gives notification to the driver.