In a watch having a balance spring and a balance cock, apparatus is provided for fastening the free end of the spring to the cock. The fastening apparatus includes a bearing block, pivotally mounted on the cock, having a generally vertically extending bearing surface for engagement with the spring. A resilient clamping member is mounted on the cock and includes a clamping arm positioned in spaced relation to the bearing surface to define a space therebetween which receives the free end of the balance spring. A fastening screw extends through the clamping arm in threaded engagement with the bearing block and has a head portion engaged with the clamping arm on the side thereof opposite the spring for urging the clamping arm towards the bearing surface when the screw is tightly threaded in the block to thereby clamp the spring between the clamping arm and the bearing surface.
