A collision avoidance device includes an electronic control unit configured to: determine whether or not a driver of a host vehicle performs turn-back steering based on a detection value of a steering angle or steering torque detected by a steering sensor of the host vehicle; and execute the collision avoidance control for avoiding a collision between the host vehicle and an obstacle in a case where the electronic control unit determines that there is a collision possibility between the host vehicle and the obstacle based on a path of the host vehicle and a position of the obstacle, wherein the electronic control unit is configured not to execute the collision avoidance control while the electronic control unit determines that the driver of the host vehicle performs turn-back steering.