Hydrogen is expected to become one of the major secondary energy sources and to be treated as important as conventional secondary energy such as electrical energy, thermal energy and so on. Effectively, to use the hydrogen energy leads to the achievement of the low carbon society that is one of the goals of the sustainable society that is aim at the modern society. However, in the industry, there are few precedents of practical use that is using hydrogen energy. In this study, hydrogen energy is applied to plastic injection molding mold heating using LmNi4.90Mn0.10 hydride. In this paper, the thermal characteristic of heating and cooling processes of the proposal system with using the heat of formations by exothermic/endothermic reversible reactions was investigated and the effectiveness of this method has been evaluated from relationship between measured surface temperature change and amount of hydrogen absorption. As results, using this proposal system, when the time cycle of the heating and cooling processes was set about 162 seconds, the mold surface temperature difference of the heating system between these processes became 55 K and the average amount of hydrogen transfer of three cycles except for first cycle was 0.80g which was 80% value of maximum amount of hydrogen absorption.