Driving assistance device and driving assistance method

A driving assistance device comprising:

• a determination unit that determines whether a brake light of a preceding vehicle located in front of a vehicle is turned on, based on a lighting state of a headlight of the preceding vehicle and an acceleration/deceleration of the preceding vehicle;
• and
• a calculation unit that calculates a target acceleration/deceleration of the vehicle, based on a determination by the determination unit of whether the brake light of the preceding vehicle is turned on;
• and
• a control unit that controls an acceleration/deceleration of the vehicle,
• wherein
• the determination unit determines that the brake light is turned on, in a case where the headlight of the preceding vehicle is turned on and the preceding vehicle is decelerated, and
• the vehicle is accelerated or decelerated according to the target acceleration/deceleration.