To provide a drum brake which is excellent in characteristics of following eccentric wear and excellent in waterproofness.

A T-shaped rod 74 is engaged with a slide cam 76 irrotationally about an axis and relatively movably in a direction vertical to the axis and crossing a pressing face 110, and therefore, when the T-shaped rod 74 is rotated around the axis, the slide cam 76 is rotated in the same direction R to press a pair of brake shoes 14, 16 in expanding directions. When the gap between the pair of brake shoes 14, 16 is not uniform, one end having a smaller gap is pressed against the rotating drum, and then, a reaction force given by the one end becomes bigger than a reaction force given by the other end. Due to difference in magnitude of the reaction forces, the slide cam 76 is moved relatively to the rod 74 in the S direction to move away from the one of the brake shoes 14, 16. Thus, the drum brake can favorably follow the eccentric wear by relative movement of the slide cam 76 following up the rotation of the T-shaped rod 74.