A vehicle collision avoidance assistance device is configured to perform forced braking or forced steering when a driver's vehicle has a possibility of colliding with an object ahead of the driver's vehicle, acquire at least one of information related to a condition of the driver's vehicle and information related to a situation around the driver's vehicle, determine, based on the acquired information, whether a request condition for requesting execution of the forced steering is satisfied and whether a forbiddance condition for forbidding the execution of the forced steering is satisfied, perform the forced braking when the request condition is not satisfied regardless of whether the forbiddance condition is satisfied, perform the forced steering when the forbiddance condition is not satisfied and the request condition is satisfied, and perform the forced braking when the forbiddance condition is satisfied though the request condition is satisfied.