a driving device configured to give driving power to a driving wheel of an own vehicle;

a braking device configured to give braking power to the driving wheel;

a periphery sensor configured to output surrounding information that is information relevant to a physical body in a periphery of the own vehicle; and

a drive assist control device configured to decide a target value of an inter-vehicle distance between a preceding vehicle and the own vehicle based on the surrounding information, and to execute follow-up control to control the driving device and the braking device such that a measured value of the inter-vehicle distance coincides with the target value, the preceding vehicle traveling in front of the own vehicle, the measured value of the inter-vehicle distance being acquired based on the surrounding information, wherein:

a first condition is defined as a condition that the inter-vehicle distance is smaller than a first threshold;

a second condition is defined as a condition that a speed of the preceding vehicle relative to the own vehicle is lower than a second threshold;

a third condition is defined as a condition that a speed of an adjacent vehicle is lower than a third threshold, the adjacent vehicle being a vehicle that travels on a lane adjacent to a lane where the own vehicle is;

a fourth condition is defined as a condition that an acceleration rate of the adjacent vehicle is lower than a fourth threshold; and

in a case where at least one of the first condition and the second condition is satisfied and where at least one of the third condition and the fourth condition is satisfied, the drive assist control device executes acceleration restraint control to control either or both of the driving device and the braking device such that an acceleration rate of the own vehicle is “0” or lower.