As the food mount board of conductivity (2) the insulated warehouse (1) is accommodated inside, preservation method of the food which features that it mounts the food (9) in the aforementioned food mount board (2), simultaneously with alternating current volts and direct current voltage it cools the food (9) when it is impressed in the food mount board (2) and retains. It flows directly straight the period when the aforementioned alternating current volts and direct current voltage are impressed simultaneously interchange simultaneous impression period, after the aforementioned direct current interchange simultaneous impression period elapses, only the aforementioned direct current or alternating current volts cools the food (9) when it is impressed in the food mount board (2) and retains. The retention device of the food which features that the insulated warehouse (1) and the food mount board of the conductivity which is accommodated in the insulated warehouse (1) (2) and the AC power supply which impresses alternating current volts in the food mount board (2) (3) and the direct voltage source which impresses direct current voltage in the food mount board (2) (4) we have, the aforementioned alternating current volts and the aforementioned direct current voltage the food mount board we impress simultaneously in (2).導電性の食品載置板(2)を保冷庫(1)内に収容するとともに、前記食品載置板(2)に食品(9)を載置し、交流電圧と直流電圧とを同時に食品載置板(2)に印加した状態で食品(9)を冷却し保存することを特徴とする食品の保存方法。前記交流電圧と直流電圧を同時に印加する期間を直流・交流同時印加期間とし、前記直流・交流同時印加期間が経過したのちは、前記直流あるいは交流電圧のみを食品載置板(2)に印加した状態で食品(9)を冷却し保存する。保冷庫(1)と、保冷庫(1)に収容した導電性の食品載置板(2)と、食品載置板(2)に交流電圧を印加する交流電源(3)と、食品載置板(2)に直流電圧を印加する直流電源(4)と備えており、前記交流電圧と前記直流電圧とを食品載置板(2)に同時に印加することを特徴とする食品の保存装置。