Disclosed are a refrigerator and a control method thereof. The refrigerator according to one aspect includes a main body having a storage chamber; a compressor configured to compress a refrigerant; a condenser configured to condense the refrigerant compressed by the compressor; an evaporation expander configured to depressurize the refrigerant condensed by the condenser; a first evaporator configured to evaporate the refrigerant depressurized by the evaporation expander and thus to cool the storage chamber; a condensing expander installed between the condenser and the evaporation expander and configured to depressurize the refrigerant condensed by the condenser; and a subsidiary condenser installed between the condensing expander and the evaporation expander and configured to condense the refrigerant depressurized by the condensing expander.