Driving assist method and driving assist device

A driving assist device for a host vehicle traveling in a host vehicle lane, comprising:

• a controller that performs a lane change control to make a lane change to an adjacent lane in which another vehicle present in the surroundings of the host vehicle is traveling,
• the driving assist device being characterized by the controller including:
• a lane change request detection unit that detects whether a presence of a request from the host vehicle to make a lane change to the adjacent lane;
• a lane change intent detection unit that detects whether there is any intention for the other vehicle traveling in the adjacent lane to make a lane change towards the host vehicle lane upon detecting the presence of the request from the host vehicle to make the lane change;
• and
• a lane-change-target-setting unit that establishes the lane-change-intending other vehicle as a vehicle designated for a place-swapping lane change, and that sets a position of a vacant area that will be created due to the lane change by the designated vehicle as a target lane change to be made by the host vehicle upon detection that there is an intent for the other vehicle to make the lane change toward the host vehicle lane;
• and
• a lane change control unit that performs a lane change control on based on the target lane change.