The invention discloses a single-shaft horizontally-arranged variable-track vibration exciter which comprises a vibrating case body, a spring and a base. The vibration exciter is characterized in that two telescopic rods are arranged on each side of the vibrating case body; the two telescopic rods are hinged with an upper connecting rod and a lower connecting rod to form a parallelogram mechanism; the two ends of the upper connecting rods, which are positioned on the two sides, are hinged with the upper pivot points of four telescopic rods and respectively fixed on a bearing seat and the vibrating case body which are positioned at the two ends of an eccentric shaft; and the two ends of the lower connecting rods are hinged with the pivot points of the lower ends of the four telescopic rodsand fixed in four arc-shaped adjuster slot holes which are formed on the base respectively. The invention has the most significant effect that different motion tracks, such as circular motion track, linear motion track and elliptic motion track, can be achieved in the same device by adjusting the slippage interval of the telescopic rods so as to meet the needs for different working conditions in the screening and feeding procedures. The vibration exciter disclosed by the invention has good excitation work-doing effects, high efficiency, low electricity consumption and low manufacturing cost, good vibration equilibrium, is convenient for maintenance, can be arranged horizontally during use and is convenient for adjustment. Besides, the traditional product can be transformed technically according to the technical scheme provided by the invention for improving the product performance.