A vibration-reducing device is applied to a scroll saw. The scroll saw includes a body, a U-frame, a block and an actuating device. The U-frame is coupled to the body, and the block and a shaft of the actuating device are eccentrically fastened to each other, and the actuating device is mounted to the body. The vibration-reducing device includes a connector and a pivot arm pivotally coupled to the body. The connector includes a third end rotatably connected to the block, and a fourth end rotatably connected to the pivot arm. When the shaft is rotated, the motion of the center of gravity of the pivot arm in a vertical direction is opposite to the motion of the center of gravity of the U-frame.