A braking device of a double bearing reel according to one embodiment of the present disclosure brakes a spool rotatably mounted on a reel body, the braking device provided with a braked unit attached to the spool, a braking unit that applies a braking force to the braked unit, an output shaft that adjusts the braking force of the braking unit according to a rotational angle, a motor capable of driving the output shaft in forward and backward directions, a reduction mechanism that transmits power while decelerating from the motor to the output shaft, a control unit that controls the motor, and a power supply that supplies electric power to the motor, the braking device provided with a watertight case that houses the motor, the reduction mechanism, the control unit, and the power supply in a watertight manner, and a waterproof unit for waterproofing on the output shaft.