A cable take-up device for a flexible flat cable routed for a slide seat slidably supported to be movable forward and backward along a longitudinal direction of a fixed rail fixed to a vehicle body, the cable take-up device comprising: - a take-up housing part configured to take up a housed portion in a drawable manner and house the housed portion inside the take-up housing part with a first cable end portion fixed to a side of a first rail end portion and a second cable end portion fixed to the slide seat, the first cable end portion being one end portion of the flexible flat cable, the first rail end portion being one end of the fixed rail, the second cable end portion being another end portion of the flexible flat cable, the housed portion being a portion of the flexible flat cable between the first cable end portion and the second cable end portion; - a take-up force generation part configured to generate take-up force in a direction of take-up of the housed portion through drawing of the flexible flat cable; and - a take-up force application part configured to apply the take-up force of the take-up force generation part to the housed portion, wherein - one of the first cable end portion and the second cable end portion is output to an outside from a take-up center of the take-up housing part, and - the take-up force generation part is disposed on an opposite side opposite to a side on which the one of the first cable end portion and the second cable end portion is output to the outside in a take-up center axis direction of the take-up housing part, characterized in that - the take-up force application part comprises a regulation part configured to regulate an intermediate portion of the housed portion, - of the housed portion, a portion disposed on a radial inside of the regulation part is defined as an inner installation portion and a portion disposed on a radial outside of the regulation part is defined as an outer installation portion, - the inner installation portion and the outer installation portion are wound in the same direction and housed, and - the inner installation portion is wound up when the outer installation portion is unwound whereas the inner installation portion is wound down when the outer installation portion is taken up. - a take-up housing part configured to take up a housed portion in a drawable manner and house the housed portion inside the take-up housing part with a first cable end portion fixed to a side of a first rail end portion and a second cable end portion fixed to the slide seat, the first cable end portion being one end portion of the flexible flat cable, the first rail end portion being one end of the fixed rail, the second cable end portion being another end portion of the flexible flat cable, the housed portion being a portion of the flexible flat cable between the first cable end portion and the second cable end portion; - a take-up force generation part configured to generate take-up force in a direction of take-up of the housed portion through drawing of the flexible flat cable; and - a take-up force application part configured to apply the take-up force of the take-up force generation part to the housed portion, wherein - one of the first cable end portion and the second cable end portion is output to an outside from a take-up center of the take-up housing part, and - the take-up force generation part is disposed on an opposite side opposite to a side on which the one of the first cable end portion and the second cable end portion is output to the outside in a take-up center axis direction of the take-up housing part, - the take-up force application part comprises a regulation part configured to regulate an intermediate portion of the housed portion, - of the housed portion, a portion disposed on a radial inside of the regulation part is defined as an inner installation portion and a portion disposed on a radial outside of the regulation part is defined as an outer installation portion, - the inner installation portion and the outer installation portion are wound in the same direction and housed, and - the inner installation portion is wound up when the outer installation portion is unwound whereas the inner installation portion is wound down when the outer installation portion is taken up.