A door opening and closing device can change a damping force of a damper when an arm rotates by opening and closing of a door. On a case 11 of the door opening and closing device 7, the arm 8 is mounted which rotates by opening and closing of the door 2. Inside the case 11, friction generating unit 22 is provided. The friction generating unit 22 has a slider 12d which moves linearly relative to the case 11 by opening and closing of the door 2 and a fixed part 21 which is fixed to the case 11 to slide the slider 12d. The friction generating unit 22 generates friction between the slider 12d and the fixed part 21. In opening and closing of the door 2, a radio of the rotation angle of the arm 8 and the amount of displacement of the slider 12d is varied.