The invention provides a transverse vibration friction-reducing drilling tool which comprises a hollow tool housing. The tool housing is internally provided with a hollow central shaft which is coaxially and rotatably arranged in a sleeving manner. The outer wall of the central shaft and the inner wall of the tool housing are radially and separately arranged for forming a drilling fluid annular hollow flowing channel. Two ends of the drilling fluid annular hollow flowing channel in the central shaft are provided with driving structures which can drive the central shaft to rotate. The central shaft is internally provided with an eccentric part which can rotate for generating transverse vibration. According to the transverse vibration friction-reducing drilling tool, a relative motion process between a drill bit and a well wall is improved through transverse vibration which is generated by the inner eccentric part, thereby reducing a friction resistance between the drill bit and the wellwall, improving extending levelness of a horizontal well and increasing drilling speed of a machine.