PURPOSE: To eliminate needs for a pump for circulating a medium thereby remarkably simplifying the shape of a device by providing storage chambers for a working solvent while having a solid electrolyte containing electrode membranes on both sides and placing them at a high temperature side or at a low temperature side reciprocally, followed by moving the solvent.

CONSTITUTION: Solid electrolyte 2 containing electrode membranes 3 and 4 respectively at both end surfaces are intervened in a vessel 1 which constitutes a generating element, and storage chambers 5 and 6 for a working solvent are formed respectively at both ends of the vessel 1. First, the storage chamber 5, in which the working solvent is filled, is placed at the high temperature side while the storage chamber 6 at the low temperature side, and subsequently generation is performed while the solvent in the storage chamber 5 is transferred to the storage chamber 6 passing through the electrolyte 2. Next, the storage chamber 6 is placed at the high temperature side while the storage chamber 5 at the low temperature side, generation is performed while the solvent in the storage chamber 6 is transferred to the storage chamber 5 passing through the electrolyte 2. Accordingly, no pump is used for moving the solvent and DC power can be provided to an external circuit provided between the electrode membranes 3 and 4.