Provided is a thawing device capable of improving the thawing rate greatly by agitation of the contents in a bag during thawing. The thawing device includes a first heater 1 and a second heater 2 to heat a bag X containing a frozen matter Z, and a supporting unit 3 to support the bag X. The first heater 1 is supported at guide grooves 5 to be movable back and forth, and descends while coming closer to the bag X, and lets a component force in the travelling direction of the self weight act as a biasing force. The second heater 2 is supported via a supporting shaft 20 that extends horizontally, and lets a pressing force act on the upper side and the lower side of the bag X alternately. An excessive pressing force acting on the bag X can be alleviated because the first heater 1 moves backward, and so the possibility of a damage of the bag X can be reduced when the second heater 2 presses the bag X in a frozen state as well.
