A heat storage material composition comprising: a higher hydrocarbon; and lauryl alcohol, the heat storage material composition satisfying all of the following conditions to: a weight ratio of the higher hydrocarbon included in the heat storage material composition is not less than 2 weight% and not more than 22 weight% with respect to 100 weight% of the heat storage material composition; the higher hydrocarbon includes not less than two types of hydrocarbons having 20 to 35 carbon atoms, a weight ratio of the not less than two types of the hydrocarbons having 20 to 35 carbon atoms included in the higher hydrocarbon being not less than 50 weight% with respect to 100 weight% of the total amount of the higher hydrocarbon included in the heat storage material composition; the higher hydrocarbon includes a hydrocarbon whose melting peak temperature in a DSC curve is not less than 35°C and not more than 70°C; a difference (ΔT) between a melting temperature of the heat storage material composition and a solidification temperature of the heat storage material composition is not more than 1.0°C; and the heat storage material composition has a degree of solidification point depression of less than 1.5°C. a higher hydrocarbon; and lauryl alcohol, the heat storage material composition satisfying all of the following conditions to: a weight ratio of the higher hydrocarbon included in the heat storage material composition is not less than 2 weight% and not more than 22 weight% with respect to 100 weight% of the heat storage material composition; the higher hydrocarbon includes not less than two types of hydrocarbons having 20 to 35 carbon atoms, a weight ratio of the not less than two types of the hydrocarbons having 20 to 35 carbon atoms included in the higher hydrocarbon being not less than 50 weight% with respect to 100 weight% of the total amount of the higher hydrocarbon included in the heat storage material composition; the higher hydrocarbon includes a hydrocarbon whose melting peak temperature in a DSC curve is not less than 35°C and not more than 70°C; a difference (ΔT) between a melting temperature of the heat storage material composition and a solidification temperature of the heat storage material composition is not more than 1.0°C; and the heat storage material composition has a degree of solidification point depression of less than 1.5°C. a weight ratio of the higher hydrocarbon included in the heat storage material composition is not less than 2 weight% and not more than 22 weight% with respect to 100 weight% of the heat storage material composition; the higher hydrocarbon includes not less than two types of hydrocarbons having 20 to 35 carbon atoms, a weight ratio of the not less than two types of the hydrocarbons having 20 to 35 carbon atoms included in the higher hydrocarbon being not less than 50 weight% with respect to 100 weight% of the total amount of the higher hydrocarbon included in the heat storage material composition; the higher hydrocarbon includes a hydrocarbon whose melting peak temperature in a DSC curve is not less than 35°C and not more than 70°C; a difference (ΔT) between a melting temperature of the heat storage material composition and a solidification temperature of the heat storage material composition is not more than 1.0°C; and the heat storage material composition has a degree of solidification point depression of less than 1.5°C.