The invention discloses an eccentric device with the amplitude automatically adjusted along with the rotation speed. The eccentric device comprises a liquid storage portion located at the center of the eccentric device, and eccentric portions located at the two ends of the eccentric device. The liquid storage portion is connected with the eccentric portions through liquid conveying channels, the widths of the liquid conveying channels are different, the lower portions of the liquid conveying channels are oblique planes, and the angles of all oblique planes are different. The eccentric device has the advantages that the amplitude of the eccentric device can be automatically adjusted through inertia forces along with changes of the rotation speed, and therefore the eccentric device can be widely applied to the field of machinery, medicine, communication and the like, and has wide market application prospects.