To provide an earthing device which can be installed in a small space at low cost.

This earthing device has a fixed cylinder 28 erected from a box 32 arranged in an earth potential unit 2 below a high potential unit 4, and a movable cylinder 24 is installed to the fixed cylinder 28 movably in a vertical direction. Between the movable cylinder 24 and the fixed cylinder 28 is provided a spring 26 which elastically pushes up the movable cylinder 24. Above the movable cylinder 24 is provided an earthing electrode 22 being butted against a high potential electrode 20 connected to the high potential unit 4. To the movable cylinder 24 is connected a strip traction body 30 comprising a conductor, and thus the earth electrode 22 is earthed to the earth potential unit 2 by the traction body 30. In the box 32 is provided a motor type winder 34 which winds the traction body 30 against the force of spring 26 to pull down the movable cylinder 24 and the earthing electrode 22.