A door opening degree adjustment device includes a check link having a stopper portion, a guide member having a guide hole, and an adjustment member. The adjustment member includes a plurality of stages of step portions and a guide projection that is inserted in the guide hole movably in the extending direction of the guide hole. The adjustment member causes the stopper portion to contact the step portions of any one of the stages, thereby restricting an opening operation caused by pivoting of the door in one direction. The guide projection is arranged on an extended line that connects the stopper portion to one of the stages of the step portions that contacts the stopper portion in the direction of the movement of the check link.