[en] In a cold fusion reaction for taking out energy by electrolyzing heavy water using a Pd cathode, a pre-treatment for heavy water absorption-releasing cycle is conducted. Further, after the pre-treatment, the heavy water is changed to new heavy water and the electrolysis is applied again. In addition, pulsative electrolysis is used. In particular, deuterium embrittlement is conducted in a gas tight vessel at high temperature and high pressure. Reaction starting sites for deuterium are previously formed to the Pd cathode by the pre-treatment to facilitate exothermic reaction for abnormal heat. The temperature difference of the abnormal heat exceeds 10degC and approaches 60degC shown in data presented by Pons, et al. Further, since the device has a gas tight structure, once after the abnormal heat reaction has occurred, the abnormal heat generation reaction is induced self-catalytically. Since electric supply is not necessary for keeping the generated abnormal heat, there are effects that the device can be moved to a place where the abnormal heat is required and abnormal heat is taken out there, and the electrolysis is applied again. (N.H.)