A refrigerator comprising: a storage chamber configured to store food; a cooler configured to supply cold into the storage chamber; a first tray assembly configured to define a portion of an ice making cell that is a space in which water is phase-changed into ice by the cold; a second tray assembly configured to define another portion of the ice making cell, the second tray assembly being connected to a driver to contact the first tray assembly in an ice making process and to be spaced apart from the first tray assembly in an ice separation process; a water supply part configured to supply the water into the ice making cell; a heater disposed adjacent to at least one of the first tray assembly or the second tray assembly; and a controller configured to control the heater and the driver, wherein the controller is configured to control the cooler so that the cold is supplied to the ice making cell after the second tray assembly moves to an ice making position when the water is completely supplied to the ice making cell, one of the first and second tray assemblies (201, 211) has a greater degree of cold transfer, which is a degree of transfer of the cold, than the other tray assembly; characterized in that the controller is configured to control the heater to be turned on in at least partial section while the cooler supplies the cold so that bubbles dissolved in the water within the ice making cell moves from a portion, at which the ice is made, toward the water that is in a liquid state to make transparent ice, wherein the first tray assembly comprises: a first tray part defining appearance; and a second tray part formed of a material different from that of the first tray part and defining the ice making cell, wherein a degree of deformation resistance of the first tray part is greater than that of the second tray part; and a third tray part in contact the first tray part, wherein the third tray part surrounds at least a portion of the first tray part. a storage chamber configured to store food; a cooler configured to supply cold into the storage chamber; a first tray assembly configured to define a portion of an ice making cell that is a space in which water is phase-changed into ice by the cold; a second tray assembly configured to define another portion of the ice making cell, the second tray assembly being connected to a driver to contact the first tray assembly in an ice making process and to be spaced apart from the first tray assembly in an ice separation process; a water supply part configured to supply the water into the ice making cell; a heater disposed adjacent to at least one of the first tray assembly or the second tray assembly; and a controller configured to control the heater and the driver, wherein the controller is configured to control the cooler so that the cold is supplied to the ice making cell after the second tray assembly moves to an ice making position when the water is completely supplied to the ice making cell, one of the first and second tray assemblies (201, 211) has a greater degree of cold transfer, which is a degree of transfer of the cold, than the other tray assembly; characterized in that the controller is configured to control the heater to be turned on in at least partial section while the cooler supplies the cold so that bubbles dissolved in the water within the ice making cell moves from a portion, at which the ice is made, toward the water that is in a liquid state to make transparent ice, wherein the first tray assembly comprises: a first tray part defining appearance; and a second tray part formed of a material different from that of the first tray part and defining the ice making cell, wherein a degree of deformation resistance of the first tray part is greater than that of the second tray part; and a third tray part in contact the first tray part, wherein the third tray part surrounds at least a portion of the first tray part. a first tray part defining appearance; and a second tray part formed of a material different from that of the first tray part and defining the ice making cell, wherein a degree of deformation resistance of the first tray part is greater than that of the second tray part; and a third tray part in contact the first tray part, wherein the third tray part surrounds at least a portion of the first tray part.