There is provided a heat storage system and a heat storage container each capable of improving a heat generation amount and a heat transport amount with a simple configuration, and a heat storage device using the above heat storage container. A heat storage system using a heat storage container having a tubular body, a chemical heat storage material accommodated in the tubular body, and a flow channel that penetrates the tubular body in a longitudinal direction, the heat storage system having a diffusion layer for transporting liquid from the flow channel to the chemical heat storage material, the liquid functioning as a reaction medium of the chemical heat storage material, wherein the liquid is transported to the flow channel, the liquid is transported to the diffusion layer, the liquid transported to the diffusion layer reacts with the chemical heat storage material, the chemical heat storage material generates heat, and the liquid is vaporized by the heat to become heat transport fluid.