A refrigerator includes a cabinet, a first inner case that defines a freezing compartment, a second inner case that defines a refrigerating compartment, a thermal siphon unit that is configured to carry a working fluid for heat transfer and that has a closed loop shape that includes a first part arranged at an outer side of the first inner case and a second part arranged at an outer side of the second inner case, and a cool air storage unit arranged in a space partitioned in the first inner case. The cool air storage unit is configured to accommodate cool air of the freezing compartment and transfer the cool air to the first part of the thermal siphon unit arranged outside of the first inner case.