A chemical heat pump comprising: a plurality of reaction sections (R1, R2) each containing a thermal storage medium (M1-3) that undergoes an exothermic reaction and an endothermic reaction; an evaporation-condensation section that contains a substance involved in the reactions of the thermal storage medium and is configured to cause phase transition of the substance between a gas phase and a liquid phase; a connection section (H18-21) connecting the reaction sections to the evaporation-condensation section; a plurality of fluid channels individually disposed so as to correspond to the reaction sections (R1, R2) such that heat exchange is caused between a fluid flowing through each of the fluid channels and the thermal storage medium contained in the corresponding reaction section; and a controller configured to control fluid-flows in the fluid channels, wherein the controller is configured to sequentially select, every time after a first period elapses, a reaction section as a heat-release reaction section from the plurality of reaction sections (R1, R2), the controller is configured to cause a fluid to flow through the fluid channel corresponding to the heat-release reaction section from a first side to a second side of the fluid channel over the first period, the fluid having a temperature lower than a transformation temperature of the thermal storage medium contained in the heat-release reaction section, so that the heat-release reaction section is set to a heat-release state in which the thermal storage medium releases heat to the fluid by the exothermic reaction over the first period, and for each of the reaction sections, after an elapse of a period of being selected as the heat-release reaction section and before beginning of a period of being selected again as the heat-release reaction section, the controller is configured to cause a fluid to flow from one side to the other side of the fluid channel over a second period, the fluid having a temperature higher than the transformation temperature of the thermal storage medium contained in the reaction section, so that the reaction section is set to a heat-storing state in which the thermal storage medium stores heat by the endothermic reaction over the second period, characterized in that the controller is configured to cause the fluid to flow in said second period from said second side of the fluid channel to the first side thereof. a plurality of reaction sections (R1, R2) each containing a thermal storage medium (M1-3) that undergoes an exothermic reaction and an endothermic reaction; an evaporation-condensation section that contains a substance involved in the reactions of the thermal storage medium and is configured to cause phase transition of the substance between a gas phase and a liquid phase; a connection section (H18-21) connecting the reaction sections to the evaporation-condensation section; a plurality of fluid channels individually disposed so as to correspond to the reaction sections (R1, R2) such that heat exchange is caused between a fluid flowing through each of the fluid channels and the thermal storage medium contained in the corresponding reaction section; and a controller configured to control fluid-flows in the fluid channels, wherein the controller is configured to sequentially select, every time after a first period elapses, a reaction section as a heat-release reaction section from the plurality of reaction sections (R1, R2), the controller is configured to cause a fluid to flow through the fluid channel corresponding to the heat-release reaction section from a first side to a second side of the fluid channel over the first period, the fluid having a temperature lower than a transformation temperature of the thermal storage medium contained in the heat-release reaction section, so that the heat-release reaction section is set to a heat-release state in which the thermal storage medium releases heat to the fluid by the exothermic reaction over the first period, and for each of the reaction sections, after an elapse of a period of being selected as the heat-release reaction section and before beginning of a period of being selected again as the heat-release reaction section, the controller is configured to cause a fluid to flow from one side to the other side of the fluid channel over a second period, the fluid having a temperature higher than the transformation temperature of the thermal storage medium contained in the reaction section, so that the reaction section is set to a heat-storing state in which the thermal storage medium stores heat by the endothermic reaction over the second period, characterized in that the controller is configured to cause the fluid to flow in said second period from said second side of the fluid channel to the first side thereof.