DRIVING ASSISTANCE METHOD AND DRIVING ASSISTANCE DEVICE

A driving assistance method for proposing a lane change and making a lane change by autonomous travel control, based on an approval action taken by a passenger, the driving assistance method causing a controller to perform processing including: when in a case of detecting a preceding vehicle traveling at a speed relatively lower than vehicle speed of an own vehicle, first distance, the first distance being distance between another vehicle in a first adjacent lane and the own vehicle, is determined to be greater than or equal to a first threshold value, starting (S2, S4, S6) to propose a lane change to the first adjacent lane; under a condition that the first distance is greater than or equal to a second threshold value, the second threshold value being smaller than the first threshold value, continuing (S34) to propose a lane change to the first adjacent lane; and when while proposing a lane change to the first adjacent lane, an approval action is taken by the passenger, causing (S34) a turn signal on a first adjacent lane side to operate.