Abstract: A cantilever includes a gear shaft, a torsion spring, and a fastening member that is fixedly mounted inside a pan-tilt housing. The gear shaft rotationally fits the fastening member, a shaft shoulder of the gear shaft is recessed in a direction parallel to an axial direction of the shaft shoulder to form an annular accommodating groove, and the gear shaft is provided with a side opening communicating with the accommodating groove. The torsion spring is mounted in the accommodating groove, a limiting end portion that is of the torsion spring and that is close to a bottom of the accommodating groove extends out of the side opening, the side opening is configured to limit a position of the limiting end portion relative to the gear shaft, and an engagement end portion extends out of the accommodating groove and is connected to the fastening member gear shaft.