The invention discloses a cantilever type coal cutter rocking arm, and belongs to the technical field of coal cutters. The cantilever type coal cutter rocking arm comprises a rocking arm shell, a cutting motor, a height adjusting gear pump, a gear transmission system, a clutch, an inner fog system, an outer fog system, a motor protective cap and a motor protecting cover, wherein the cutting motor is fixed on the rocking arm shell through a bolt, and the cutting motor is connected with the gear transmission system through the clutch; the height adjusting gear pump is arranged on the gear transmission system, the motor protective cap and the motor protecting cover are arranged outside the cutting motor, a cable, an oil pipe and the height adjusting gear pump; and a water channel of the inner fog system is a rigid channel, and oil drain holes are formed in the side surface and the bottom surface of the rocking arm. The cantilever type coal cutter rocking arm provided by the invention has the beneficial effects that the overall structure is compact, the change and disassembly and assembly of the motor are convenient, the inner and outer fog systems are safe and reliable, the temperature of a rocking arm gear box can be effectively reduced, and the oil drain is convenient; and the height adjusting gear pump is placed on the rocking arm, the length of a coal cutter is effectively reduced, the support is easy, and a water pipe is prevented from being damaged.