DRIVING ASSISTANCE DEVICE, VEHICLE, AND DRIVING ASSISTANCE METHOD

A driving assistance device comprises: an information display unit configured to display travel information based on the driving assistance function based on a power supply from a power source mounted on a vehicle having a driving assistance function; an information notification unit provided on a steering wheel of the vehicle and configured to make a notification of an operation state of the driving assistance function by turning on or off; a notification control unit configured to operate based on a power supply from the power source and control the notification based on operation information indicating the operation state of the driving assistance function; and an alarm unit connected to the notification control unit via a communication unit and capable of outputting an alarm based on power of an internal power source different from the power source.