Provided is a method of controlling an ice-detaching temperature of an icemaker, including a first step of performing an ice-making operation in an ice-making unit, and counting a required ice-making time period from a starting point in time of the ice-making operation to an end point in time of the ice-making operation; a second step of acquiring the counted required ice-making time period, and acquiring an ambient temperature from an external temperature sensor; a third step of determining a variable ice-detaching time period, depending on the acquired ambient temperature and the acquired required ice-making time period; and a fourth step of using the determined ice-detaching time period to perform an ice-detaching operation. Ice of a cold plate is completely separated from the cold plate during an ice-detaching operation under conventional temperature conditions and even under harsh environments, preventing icemaker failure and increasing ice-making capacity.