A door opening and closing device includes a slider and a main link mechanism. The slider moves along a roof of the vehicle body in a front-rear direction, while supporting a proximal end portion of a back door in such a way as to be rotatable around an axis extending in a width direction. The main link mechanism includes one end and an opposite end rotatably coupled to the vehicle body and the back door, respectively. The main link mechanism adjusts a posture of the back door, depending on a door opening degree by changing a distance between a coupling point to the vehicle body and a coupling point to the back door. The main link mechanism decreases the distance as the door opening degree becomes larger.