A bell mounted in one of at least one brake lever of a bicycle is disclosed. The brake lever includes two brake levers each including an opening section. In one embodiment, the bell includes a sounding section in the opening section and including a hollow cylinder, an annular flange having one open end in communication with inside of the cylinder, a first spring biased between an inner wall of the brake lever and the cylinder with the flange disposed therein, a second spring in the cylinder and having one end engaged with the end of the cylinder, and a bolt driven through the second spring, the flange, and the first spring to have one end threadedly secured in the brake lever and a head urging against the second spring; and a spring biased striking section pivotably secured onto the brake lever and including a lever and a clapper.