Abstract: A collision avoidance device for avoiding collision with an object in a door zone of a vehicle, including a sensing module, a damping module and a control unit. Upon detecting an object moving toward a door of the vehicle, the sensing module calculates a velocity of the object. The control unit controls the damping module to apply a resistance force to a pivot unit that pivots the door for enabling the door to rotate at most at an initial rotational speed without detection of an object, a first rotational speed slower than the initial rotational speed when the velocity is smaller than a predetermined value, or a second rotational speed slower than the first rotational speed when the velocity is greater than the predetermined value.