Quick-release device of a bicycle brake cable

A quick-release device of a bicycle brake cable, comprising a main frame adapted to be mounted to a handlebar of a bicycle, a lever pivotally mounted to the main frame and a push device mounted in the main frame to normally push the lever for maintaining the tension of the brake cable, the lever having a pivot point that divides the lever into a holding section and a drive section, wherein the drive section is received in the main frame when the lever is in a free condition, the drive section of the lever having a push face formed on one side thereof and facing the main frame, and a groove defined in the drive section between the push face and the pivot point of the lever, a pusher mounted to a free end of the drive section, the pusher adapted to push an outer tube of the brake cable for braking a wheel when the holding section is squeezed, the push device including an axle rotatably extending through the main frame, the axle having an enlarged head facing the drive section, the enlarged head having a block extending therefrom and abutting against the push face when the lever is in a free condition, a pivot extending from the enlarged head and running through the main frame, a torsion spring and a knob sequentially sleeved on and mounted to the pivot after the pivot extending through the main frame, the knob adapted to rotate the axle and the torsion spring providing a restitution force to the axle after being rotated.