Abstract: A disk brake device comprises a brake lever 3A toward which a tilting force is applied in opening operation. This brake lever 3A is formed at its lower end with an outwardly protruding stopper 58 into which an adjusting bolt 56 is screwed vertically. A base seat 59 is provided on a base plate 1 immediately under the stopper. A pinion 61 is fitted over an upper end of the adjusting bolt 56 via a one-way clutch 60 so as to rotate the adjusting bolt 56 only in a direction of fasting the same downward. A rack 67, which is supported by the base plate 1, is meshed with the pinion to have a predetermined backlash and to extend in a direction of swing of the brake levers 3A, 3B. This disk brake device allows to assuredly maintain the brake levers 3A, 3B at equally opened positions at left and right in a brake releasing condition, even if brake linings 9A, 9B are worn out and adjustment is made by an automatic lining wear adjusting unit 53 to automatically decrease the gap caused by wear of the brake linings 9A, 9B.