An SRC includes a stator; a rotator rotatably attached to the stator; and a stack-type cable accommodated in an annular accommodation space defined by the stator and the rotator. The stack-type cable includes a transmission path FC including a pair of transmission path conductors and laminate sheets covering the pair of transmission path conductors and also includes a dummy FC that is provided on a front surface of the transmission path FC and is formed of laminate sheets not including a flat rectangular conductor, the transmission path FC and the dummy FC being stacked on each other; the stack-type cable further includes a grease that causes the transmission path FC and the dummy FC stacked on each other to adhere to each other; and a width-direction interval between the pair of transmission path conductors is set to smaller than, or equivalent to, a conductor width of each transmission path conductor.