PROBLEM TO BE SOLVED: To provide a method and a device for cooling and homogenizing foundry sand with reduced energy consumption, reduced installation space and economy. SOLUTION: A mixing and conveying device 4 provided on the device for cooling and homogenizing the foundry sand is always kept in a vacuum state, controls water inflow, and is provided on a suction part 14 for the water vapor, thereby drawing the heat of evaporation from the sand 2 by the water evaporating due to the reduced pressure, cooling and reusing the water 17 obtained by condensing the water vapor with a condenser 11. Coupled locks 3, 23 are provided on the inlet and outlet ends of the mixing and conveying device 4, through which the sand 2 enters and leaves the reduced pressure area.