Provided is a refrigerator including a cabinet having a refrigerating compartment and a freezing compartment defined therein, and an ice maker disposed in the freezing compartment, wherein the ice maker includes an upper tray made of an elastic material, and having a plurality of hemispherical upper chambers defined therein, a lower tray made of an elastic material, wherein the lower tray comes into contact with the upper tray by pivoting to define a plurality of spherical ice chambers therebetween, a driver for pivoting the lower tray to open and close the upper tray and the lower tray, and each rib formed along a circumference of each upper chamber or each lower chamber in contact with each other.