Heat storage material composition and heat storage material

A heat storage material composition contains a styrene-ethylene-ethylene-propylene-styrene copolymer and a paraffin-based wax. The heat storage material composition preferably further contains a paraffin-based process oil that softens the styrene-ethylene-ethylene-propylene-styrene copolymer. Also, the heat storage material composition preferably contains not less than 300 parts by mass and not more than 1000 parts by mass of the wax with respect to 100 parts by mass of the styrene-ethylene-ethylene-propylene-styrene copolymer.