In a phase-change cooling apparatus including an indoor unit and an outdoor unit, a configuration to prevent dew condensation in the indoor unit causes the cooling performance to decrease; therefore, a refrigerant circulating apparatus according to an exemplary aspect of the present invention includes refrigerant-liquid thermal equilibrium means for mixing a first refrigerant liquid with a second refrigerant liquid and sending a reflux refrigerant liquid composed of the first refrigerant liquid and the second refrigerant liquid, the first refrigerant liquid being a liquid-phase refrigerant included in a gas-liquid two-phase refrigerant flowing in from heat receiving means, the second refrigerant liquid arising due to the gas-liquid two-phase refrigerant cooled by heat radiating means; a refrigerant passage configured for the gas-liquid two-phase refrigerant and the reflux refrigerant liquid to circulate between the heat receiving means and the refrigerant-liquid thermal equilibrium means; refrigerant-liquid reflux means for refluxing the reflux refrigerant liquid to the heat receiving means through the refrigerant passage; and refrigerant-liquid flow control means for controlling a flow rate of the reflux refrigerant liquid.