Refrigerator

An ice maker comprising:

• a first tray assembly configured to define a portion of an ice making cell having a space in which water is phase-changed into ice by cold air;
• a second tray assembly configured to define another portion of the ice making cell;
• and
• a heater disposed adjacent to at least one tray assembly of the first tray assembly or the second tray assembly,
• wherein the at least one tray assembly comprises a tray and a tray case to support the tray,
• the tray includes a first portion defining at least a portion of the ice making cell and made of a flexible material, and
• the first portion has different degree of heat transfer in a direction along an outer circumferential surface of the ice making cell to reduce transfer of heat, the heat being transferred from the heater to one tray assembly of the first and second tray assemblies, to an ice making cell defined by the other tray assembly of first and second tray assemblies.