A driving assistance device (1) includes: a somatic nervous system activity detector (11) detecting a somatic nervous system activity, which is a physical activity, of a driver in association with steering of a vehicle； an autonomic nervous system activity detector (12) detecting an autonomic nervous system activity, which is a mental activity, of the driver in association with the steering of the vehicle； a somatic nervous system activity controller (perception amount controller (2)) which is operable to control the somatic nervous system activity； an autonomic nervous system activity controller (sound effect generator (3)) which is operable to control the autonomic nervous system activity； and a psychosomatic state controller (balance controller (14)). The psychosomatic state controller causes the somatic nervous system activity controller and the autonomic nervous system activity controller to operate such that the two activities shift to the same side with respect to increase and decrease.
