<p>Disclosed is a refrigeration circuit which employs a cooling medium comprising a compound having a double bond, wherein an oxygen adsorbent is provided therein. The oxygen adsorbent may be provided together with a desiccant agent in a receiver. The oxygen adsorbent provided in the refrigeration circuit can effectively prevent the cooling medium from being changed in its composition, and therefore enables to provide a refrigeration circuit which can exhibit its freezing ability stably over a long period and has excellent reliability and durability.</p>
