A method may produce a heat regenerating material particle, including: preparing a slurry by adding a powder of the heat regenerating substance to an alginic acid aqueous solution and mixing the powder of the heat regenerating substance and the aqueous alginic acid solution; and forming a particle by gelling the slurry by dropping the slurry into a gelling solution. The gelling solution may include a metal element including calcium (Ca), manganese (Mn), magnesium (Mg) beryllium (Be), strontium (Sr), aluminum (Al), iron (Fe), copper (Cu), nickel (Ni), and cobalt (Co). The forming may involve controlling the gelation time so that a concentration of the metal element in a first region of the particle becomes lower than a concentration of the metal element in a second region. The second region may be closer to an outer edge of the particle compared to the first region.