An ice making system includes: a tank that stores a medium to be cooled; an ice making machine that cools the medium and makes ice; a pump that circulates the medium between the tank and the ice making machine; a de-icing mechanism that performs a de-icing operation of heating and melting the medium in the ice making machine; and a control device that controls operations of the ice making machine, the pump, and the de-icing mechanism. The ice making machine includes: a cooling chamber in which the medium is cooled; a blade mechanism that rotates in the cooling chamber and disperses the ice; a detector that detects a locked state of the blade mechanism; and a first temperature sensor that is disposed at a discharge port of the cooling chamber and detects a temperature of the medium discharged from the cooling chamber.