To improve the thermal efficiency and the convenience at the time of usage by a method wherein a latent heat storing material wherein in the cylinder, an body to be kept hot is inserted, a heat insulating material which surrounds the outside of the cylindrical latent heat storing material, and a transparent cover which is fitted on the cylindrical latent heat storing material are provided.

A hot insulation material 3 is constituted of a latent heat storing material 1 and a container 2 made of TPX, and a heat insulation container 6 is constituted of a heat insulating material 4 made of foamed polyurethane, and an exterior material 5 which is made of a quilted fabric. When the exterior material is made of a quilt, the exterior material itself has a heat insulating effect, and it is more preferable than plastic material from the viewpoint of the hot insulation effect as well. Also, a cap 8 is made of a transparent plastic so that the inside can be seen through. By this method, a hot insulation container and a hot insulation bag of which the convenience is high, which are inexpensive and light-weight, wherein safety is high, and which can be repeatedly used, are obtained.