A braking device for a driving shaft, which is used for a robot articulation, the braking device comprising: a brake ring coupled to the driving shaft in such a manner as to rotate according to rotation of the driving shaft; a support frame in use fixed to an interior of the robot articulation; two brake wings (130, 131) rotatable around brake shafts formed on the support frame and each of the two brake wings (130, 131) having a locking protrusion (135, 136) adapted to stop the rotation of the driving shaft through physical interference with at least one of locking pieces of the brake ring; position regulators adapted to rotate the brake wings to allow positions of the locking protrusions to be moved; and elastic members adapted to apply elastic forces to the brake wings rotating, wherein the locking protrusions (135, 136) are moved between a first position located inside a rotation radius of the locking pieces and a second position located outside the rotation radius of the locking pieces by rotation of the brake wings, so that if the locking protrusions (135, 136) are moved to the first position, the locking protrusions (135, 136) physically interfere with the locking pieces to stop the rotation of the driving shaft, characterized in that the brake ring has four of the locking pieces with the locking pieces being cross-shaped and with an angle of 90° between two adjacent cross-shaped locking pieces, and the two locking protrusions (135, 136) formed on the two brake wings (130, 131) are positioned higher than positions of two locking pieces opposite to each other, and bi-directional gaps rotatable by a given angle α1 in a clockwise direction and a gap rotatable by a given angle α1 in a counter-clockwise direction, corresponding to the positions of the two locking protrusions (135, 136) are provided when the two locking protrusions (135, 136) are moved to the first position. a brake ring coupled to the driving shaft in such a manner as to rotate according to rotation of the driving shaft; a support frame in use fixed to an interior of the robot articulation; two brake wings (130, 131) rotatable around brake shafts formed on the support frame and each of the two brake wings (130, 131) having a locking protrusion (135, 136) adapted to stop the rotation of the driving shaft through physical interference with at least one of locking pieces of the brake ring; position regulators adapted to rotate the brake wings to allow positions of the locking protrusions to be moved; and elastic members adapted to apply elastic forces to the brake wings rotating, wherein the locking protrusions (135, 136) are moved between a first position located inside a rotation radius of the locking pieces and a second position located outside the rotation radius of the locking pieces by rotation of the brake wings, so that if the locking protrusions (135, 136) are moved to the first position, the locking protrusions (135, 136) physically interfere with the locking pieces to stop the rotation of the driving shaft, the brake ring has four of the locking pieces with the locking pieces being cross-shaped and with an angle of 90° between two adjacent cross-shaped locking pieces, and the two locking protrusions (135, 136) formed on the two brake wings (130, 131) are positioned higher than positions of two locking pieces opposite to each other, and bi-directional gaps rotatable by a given angle α1 in a clockwise direction and a gap rotatable by a given angle α1 in a counter-clockwise direction, corresponding to the positions of the two locking protrusions (135, 136) are provided when the two locking protrusions (135, 136) are moved to the first position.