Abstract: An ice maker equipped in a refrigerator includes a sealed water tank, a water reservoir supplied with water from the water reservoir by the effect of a difference between water heads until the water reaches a predetermined water level, every time the level of the water reserved therein is decreased below the predetermined water level, a measuring vessel communicated to the water reservoir through a relatively small water path so that the water is supplied thereto from the water vessel by way of the difference in the water heads until the water level corresponding to the water level in the water reservoir is reached therein, the measuring vessel having a lid portion disposed so as to horizontally partition the interior of the measuring vessel at a water level position, an ice tray disposed in the ice-making compartment, and a pump for supplying the ice tray with the water reserved in the measuring vessel.