To reduce the weight of a drum brake and its cost by increasing the strength of an anchor mounting portion at its periphery which receives braking torque, without increasing the plate thickness of a back plate.

A pair of ledge faces 24, 24 are protruded on both sides of the anchor mounting portion at the outer periphery of the back plate. A pair of reinforcing ribs 18, 18 protruded toward the inner periphery of the back plate are formed on both sides of the anchor mounting portion at the inner periphery of the back plate by bossing a plate material for the back plate 2 to the side of an inner portion. The reinforcing ribs 18, 18 are formed in symmetry with respect to a center line L1 of the anchor mounting portion 21 in the radial direction of the back plate.