A device for absorbing harness slack is disclosed wherein a leaf spring (resilient member) 37 is provided with a harness-guide member 34 which supports a curved portion 33 of a wire harness 32 slidably. The harness-guide member 34 has an upper surface (harness-support member) 38 curved throughout its length toward the curved portion 33. Alternatively, the leaf spring 37 may be provided with the curved harness-guide member 34 rotatably through a coupling member 36. Also alternatively, a protector protecting the curved portion 33 of the wire harness 32 may be provided with the curved harness-guide member 34 rotatably, and the leaf spring 37 may urge the harness-guide member 34 through such as a cap in a direction of absorbing harness slack slidably. Also alternatively, the upper surface 38 may compose a groove curved in a circumferential direction of the wire harness.