A heat storage device comprising: a heat-storage container that stores a heat-storage material used for latent heat storage, and has a heat-storage material layer containing the heat-storage material, and formed at a bottom portion thereof; a supply pipe that supplies the heat-storage material layer with a heat exchange medium smaller in specific gravity than the heat-storage material from the outside of said heat-storage container into the heat-storage layer; a discharge pipe that discharges the heat exchange medium supplied into the heat-storage material layer to the outside of said heat-storage container; and a plurality of intra-heat-storage-material-layer members that are arranged in an up/down direction in the heat-storage material layer, and are formed by metal plates (8; 10) or pipes (11; 12), wherein said intra-heat-storage-material-layer members are arranged so that upper ends of said intra-heat-storage-material-layer members are disposed at a height equal to or more than a vicinity of an upper surface level of the heat-storage material layer, characterized in that the heat-storage device comprises a perforated plate that is horizontally attached to a lower end portion of said heat-storage container so as to partition said heat-storage container into two spaces delimited in an up/down direction, wherein: a lower end of said supply pipe and said perforated plate are connected with each other such that the heat exchange medium can be supplied to the inside of said heat-storage container below said perforated plate via said supply pipe, and when said intra-heat-storage-material-layer members are formed by metal plates (8; 10), the metal plates (8; 10) are in contact with the supply pipe and the perforated plate, and when said intra-heat-storage-material-layer members are formed by pipes (11; 12), the pipes (11; 12) are in contact with the perforated plate and through holes of the perforated plate are disposed outside and inside the pipes (11; 12). a heat-storage container that stores a heat-storage material used for latent heat storage, and has a heat-storage material layer containing the heat-storage material, and formed at a bottom portion thereof; a supply pipe that supplies the heat-storage material layer with a heat exchange medium smaller in specific gravity than the heat-storage material from the outside of said heat-storage container into the heat-storage layer; a discharge pipe that discharges the heat exchange medium supplied into the heat-storage material layer to the outside of said heat-storage container; and a plurality of intra-heat-storage-material-layer members that are arranged in an up/down direction in the heat-storage material layer, and are formed by metal plates (8; 10) or pipes (11; 12), wherein said intra-heat-storage-material-layer members are arranged so that upper ends of said intra-heat-storage-material-layer members are disposed at a height equal to or more than a vicinity of an upper surface level of the heat-storage material layer, characterized in that the heat-storage device comprises a perforated plate that is horizontally attached to a lower end portion of said heat-storage container so as to partition said heat-storage container into two spaces delimited in an up/down direction, wherein: a lower end of said supply pipe and said perforated plate are connected with each other such that the heat exchange medium can be supplied to the inside of said heat-storage container below said perforated plate via said supply pipe, and when said intra-heat-storage-material-layer members are formed by metal plates (8; 10), the metal plates (8; 10) are in contact with the supply pipe and the perforated plate, and when said intra-heat-storage-material-layer members are formed by pipes (11; 12), the pipes (11; 12) are in contact with the perforated plate and through holes of the perforated plate are disposed outside and inside the pipes (11; 12). a lower end of said supply pipe and said perforated plate are connected with each other such that the heat exchange medium can be supplied to the inside of said heat-storage container below said perforated plate via said supply pipe, and when said intra-heat-storage-material-layer members are formed by metal plates (8; 10), the metal plates (8; 10) are in contact with the supply pipe and the perforated plate, and when said intra-heat-storage-material-layer members are formed by pipes (11; 12), the pipes (11; 12) are in contact with the perforated plate and through holes of the perforated plate are disposed outside and inside the pipes (11; 12).