A cold water supply system that is configured to cool water flowing through a first water pipe and a second water pipe, and to supply the water cooled to a cooling load, the cold water supply system comprising the first water pipe, the second water pipe, at least one independent refrigerant circuit unit (10 1, 10 2,..., 10 M), at least one composite unit (2 1, 2 2,..., 2 N), and a controller, wherein the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) and the composite unit (2 1, 2 2,..., 2 N) are connected in parallel by the first water pipe and the second water pipe, the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) includes a first compressor and a first water heat exchanger configured to exchange heat between refrigerant and the water flowing from the first water pipe to the second water pipe to cool the water; the composite unit (2 1, 2 2,..., 2 N) is configured to cool the water flowing from the first water pipe to the second water pipe; and the controller is configured to control operation of the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) and operation of the composite unit (2 1, 2 2,..., 2 N), the composite unit (2 1, 2 2,..., 2 N) includes a free cooling unit (20 1, 20 2,..., 20 N) including a pump and a second water heat exchanger configured to exchange heat between a heat medium and the water to cool the water, and a coupled refrigerant circuit unit (10 21, 10 22,..., 10 2N) connected in series with the free cooling unit (20 1, 20 2,..., 20 N) along the flow of water from the first water pipe to the second water pipe and including a second compressor and a third water heat exchanger configured to exchange heat between refrigerant and the water to cool the water, and the controller is configured to control an operating frequency of the first compressor, an operating frequency of the second compressor, and an operating frequency of the pump based on a temperature of the water flowing out from the second water pipe. the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) and the composite unit (2 1, 2 2,..., 2 N) are connected in parallel by the first water pipe and the second water pipe, the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) includes a first compressor and a first water heat exchanger configured to exchange heat between refrigerant and the water flowing from the first water pipe to the second water pipe to cool the water; the composite unit (2 1, 2 2,..., 2 N) is configured to cool the water flowing from the first water pipe to the second water pipe; and the controller is configured to control operation of the independent refrigerant circuit unit (10 1, 10 2,..., 10 M) and operation of the composite unit (2 1, 2 2,..., 2 N), the composite unit (2 1, 2 2,..., 2 N) includes a free cooling unit (20 1, 20 2,..., 20 N) including a pump and a second water heat exchanger configured to exchange heat between a heat medium and the water to cool the water, and a coupled refrigerant circuit unit (10 21, 10 22,..., 10 2N) connected in series with the free cooling unit (20 1, 20 2,..., 20 N) along the flow of water from the first water pipe to the second water pipe and including a second compressor and a third water heat exchanger configured to exchange heat between refrigerant and the water to cool the water, and a free cooling unit (20 1, 20 2,..., 20 N) including a pump and a second water heat exchanger configured to exchange heat between a heat medium and the water to cool the water, and a coupled refrigerant circuit unit (10 21, 10 22,..., 10 2N) connected in series with the free cooling unit (20 1, 20 2,..., 20 N) along the flow of water from the first water pipe to the second water pipe and including a second compressor and a third water heat exchanger configured to exchange heat between refrigerant and the water to cool the water, and the controller is configured to control an operating frequency of the first compressor, an operating frequency of the second compressor, and an operating frequency of the pump based on a temperature of the water flowing out from the second water pipe.