A drum brake apparatus for braking a vehicle, comprising: a wheel cylinder assembly (6,6A,6B,6C) configured to expand a pair of brake shoes (3,4), the wheel cylinder assembly (6,6A,6B,6C) comprising: a cylinder body; a pair of pistons (31,32) brought into contact with the respective brake shoes (3,4) to expand the brake shoes (3,4); a control lever configured to feed back a control force in accordance with a brake torque to one of the pistons (31,32); and a control valve configured to restrain an increase of the brake torque by closing a fluid path arranged in the cylinder body when the brake torque exceeds a reference, wherein the cylinder body has a shape of a single straight pipe with both ends which are opened, and the cylinder body includes a first cylinder portion for the one of the pistons on one end side of the both ends and a second cylinder portion for the other of the pistons on the other end side of the both ends, and wherein a valve seat of the control valve is arranged between the first cylinder portion and the second cylinder portion, and the fluid path is formed in the valve seat, and a valve body configured to seat on the valve seat by cooperatively moving with a returning movement of the one of pistons so as to close the fluid path, characterized in that the valve seat is restrained in position by a stop ring fixed to a groove portion of a cylinder inner periphery of the cylinder body; and the valve body is mounted in a recess portion formed on the one of pistons. a wheel cylinder assembly (6,6A,6B,6C) configured to expand a pair of brake shoes (3,4), the wheel cylinder assembly (6,6A,6B,6C) comprising: a cylinder body; a pair of pistons (31,32) brought into contact with the respective brake shoes (3,4) to expand the brake shoes (3,4); a control lever configured to feed back a control force in accordance with a brake torque to one of the pistons (31,32); and a control valve configured to restrain an increase of the brake torque by closing a fluid path arranged in the cylinder body when the brake torque exceeds a reference, wherein the cylinder body has a shape of a single straight pipe with both ends which are opened, and the cylinder body includes a first cylinder portion for the one of the pistons on one end side of the both ends and a second cylinder portion for the other of the pistons on the other end side of the both ends, and wherein a valve seat of the control valve is arranged between the first cylinder portion and the second cylinder portion, and the fluid path is formed in the valve seat, and a valve body configured to seat on the valve seat by cooperatively moving with a returning movement of the one of pistons so as to close the fluid path, characterized in that the valve seat is restrained in position by a stop ring fixed to a groove portion of a cylinder inner periphery of the cylinder body; and the valve body is mounted in a recess portion formed on the one of pistons. a cylinder body; a pair of pistons (31,32) brought into contact with the respective brake shoes (3,4) to expand the brake shoes (3,4); a control lever configured to feed back a control force in accordance with a brake torque to one of the pistons (31,32); and a control valve configured to restrain an increase of the brake torque by closing a fluid path arranged in the cylinder body when the brake torque exceeds a reference, wherein the cylinder body has a shape of a single straight pipe with both ends which are opened, and the cylinder body includes a first cylinder portion for the one of the pistons on one end side of the both ends and a second cylinder portion for the other of the pistons on the other end side of the both ends, and wherein a valve seat of the control valve is arranged between the first cylinder portion and the second cylinder portion, and the fluid path is formed in the valve seat, and a valve body configured to seat on the valve seat by cooperatively moving with a returning movement of the one of pistons so as to close the fluid path, characterized in that the valve seat is restrained in position by a stop ring fixed to a groove portion of a cylinder inner periphery of the cylinder body; and the valve body is mounted in a recess portion formed on the one of pistons.