A wire feeding unit for feeding a welding wire in a torch cable of a welding robot, the torch cable passing through the inside of an upper arm in its direction, includes a body member, which is mounted on an inner periphery of the upper arm in a state of being freely pivotable around the axis of the upper arm, and to which the torch cable is installed, and a feed roller mounted to the body member in a state of being freely rotatable around an axis orthogonal to the axis of the arm. Here, the welding wire exposed out of the torch cable is in contact with the circumferential surface of the feed roller and is fed by the rotation of the feed roller in a direction of the axis of the upper arm. According to the configuration like this, when an arm is pivoted, the torch cable passing through the arm is able to be prevented from being twisted.