The invention provides a cooling device. The cooling device is connected with a server, cools down the server, and comprises a cabinet and a heat exchanger, wherein the heat exchanger is arranged in a cabinet and is provided with a first circulating pipeline, a second circulating pipeline and a cooling pipeline; the first circulating pipeline, the second circulating pipeline and the cooling pipeline are in heating contact with one another; the first circulating pipeline is connected to a first load pipeline of the server so as to cool down gas entering the server; the second circulating pipeline is connected to a second load pipeline of the server, and the second circulating pipeline is connected with an electronic element in the server via the second load pipeline to cool down the electronic element; one end of the cooling pipeline is connected to a cooling fluid source, and the other end of the cooling pipeline is used for draining cooling fluid; and the modular cooling device is formed by the cabinet and the heat exchanger. When a servo framework consisting of the cooling device and the server is adjusted, the modular cooling device can be changed.