ARM POWER SUPPLY DEVICE

An object is to prevent a wire harness from hanging down from a rotational base end side of a second arm and from shaking in the upward and downward direction when the wire harness is fixed only to a rotation tip side of the second arm axially supported to a first arm and the second arm rotates and is positioned on a lower side. In order to solve the above object, an arm power supply device (1) includes a first arm (3) configured to be rotatably and axially supported to a base member (2), and a second arm (8) configured to be rotatably and axially supported on a rotation tip side of the first arm. The second arm includes a harness insertion groove (59) and a harness fixing portion (58) on a rotation tip side. There is employed a configuration in which an outer wall (64) of the harness insertion groove is extended longer than an inner wall (66) on a rotational base end side, the outer wall includes an inclined or bent guide wall portion (67) on the rotational base end side, and a wire harness (28) is guided upward along the guide wall portion when the second arm rotates to the lower side.