Abstract: A collision avoidance support device configured to determine whether or not automatic braking for decelerating an own vehicle should be executed based on a predetermined determination condition in a situation where it is determined that there is a possibility of a collision between another vehicle traveling on a road intersecting an own vehicle road and the own vehicle, to decelerate the own vehicle by the automatic braking when it is determined that the automatic braking should be executed, and further to, when it is determined that the own vehicle road is a non-priority road, make it easier to be determined that the automatic braking should be executed by relaxing the predetermined determination condition as compared to when it is determined that the own vehicle road is not a non-priority road.