A quick-release device for a bicycle brake including a first brake arm, a second brake arm, and a brake cable terminated at the second brake arm, the quick-release device is provided with a lever including a long part and a short part pivotably secured to a top of the second brake arm; and an attachment assembly for securing the brake cable to a joining portion of the long part and the short part. A rotation of the lever in a first direction loosens the brake cable and increases a distance between the first brake arm and the second brake arm. A rotation of the lever in a second direction contrary to the first direction tightens the brake cable and decreases the distance between the first brake arm and the second brake arm.