Driving assistance device

A driving assistance device configured to assist driving of a driver in a subject vehicle, the driving assistance device comprising:

• a map acquisition unit configured to acquire a surrounding area map that indicates an object state in a surrounding area of the subject vehicle to define a positional relation between objects;
• a traveling determination unit configured to determine, based on the surrounding area map acquired by the map acquisition unit, whether the subject vehicle is travelable in an assistance target scene that is at least one of a passing-through scene and a passing-each-other scene;
• a guide generation unit configured to generate a guide that guides the subject vehicle in the assistance target scene based on the surrounding area map acquired by the map acquisition unit and configured to adjust relative positions of an obstacle to the subject vehicle in the assistance target scene and the guide in the surrounding area map in accordance a reference position information;
• a steering assistance unit configured to perform a steering assistance to assist steering of the subject vehicle by the driver in accordance with the guide generated by the guide generation unit when the traveling determination unit determines that the subject vehicle is travelable;
• and
• a reference updating unit configured to update the reference position information in accordance with a degree of deviation between the guide generated by the guide generation unit and an actual trajectory along which the subject vehicle passes during the steering assistance by the steering assistance unit.