A chemical heat accumulator includes a receptacle, a first reaction vessel, and a second reaction vessel. The first reaction vessel is hermetically connected to the receptacle and supplied with water from the receptacle. The first reaction vessel contains a chemical compound that causes a hydration reaction with the water from the receptacle to generate water vapor by a heat of reaction, and causes a dehydration reaction by receiving heat. The second reaction vessel is hermetically connected to the first reaction vessel and supplied with the water vapor from the first reaction vessel. The second reaction vessel contains a chemical heat storage material that generates heat by causing a hydration reaction with the water vapor from the first reaction vessel and stores heat through a dehydration reaction caused by receiving heat. The chemical heat storage material is thermally in contact with an object to be heated.