A polymer physical property prediction device comprising: a substructure number calculating unit configured to read a structural unit from a storage unit and use the structural unit to calculate numbers each indicating how many substructures are in a polymer, the polymer being formed of repetition of the structural unit; an atom calculating unit configured to calculate a number indicating how many atoms are in the structural unit; a substructure number density calculating unit configured to calculate number densities of the substructures from the numbers of substructures and the number of atoms in the structural unit; a regression model construction unit configured to construct a regression model that predicts a physical property value by using an experimental value of a physical property of the polymer, experimentally obtained in advance, and the number densities of the substructures, the experimental value being obtained from the storage unit; a polymer structure input unit configured to input a polymer structure of which the physical property value is to be predicted; and a polymer physical property prediction unit configured to predict the physical property value corresponding to the input polymer structure by using the regression model; wherein the polymer physical property prediction device further comprises: a model structure generator configured to generate a model structure by repeatedly using the structural unit obtained from the storage unit; and a dimension reduction unit configured to remove part of a structure descriptor representing the number densities of the substructures calculated by the substructure number density calculating unit, wherein the substructure number calculating unit and the atom calculating unit calculate the numbers of substructures and the number of atoms from the generated model structure. a substructure number calculating unit configured to read a structural unit from a storage unit and use the structural unit to calculate numbers each indicating how many substructures are in a polymer, the polymer being formed of repetition of the structural unit; an atom calculating unit configured to calculate a number indicating how many atoms are in the structural unit; a substructure number density calculating unit configured to calculate number densities of the substructures from the numbers of substructures and the number of atoms in the structural unit; a regression model construction unit configured to construct a regression model that predicts a physical property value by using an experimental value of a physical property of the polymer, experimentally obtained in advance, and the number densities of the substructures, the experimental value being obtained from the storage unit; a polymer structure input unit configured to input a polymer structure of which the physical property value is to be predicted; and a polymer physical property prediction unit configured to predict the physical property value corresponding to the input polymer structure by using the regression model; wherein the polymer physical property prediction device further comprises: a model structure generator configured to generate a model structure by repeatedly using the structural unit obtained from the storage unit; and a dimension reduction unit configured to remove part of a structure descriptor representing the number densities of the substructures calculated by the substructure number density calculating unit, wherein the substructure number calculating unit and the atom calculating unit calculate the numbers of substructures and the number of atoms from the generated model structure. a model structure generator configured to generate a model structure by repeatedly using the structural unit obtained from the storage unit; and a dimension reduction unit configured to remove part of a structure descriptor representing the number densities of the substructures calculated by the substructure number density calculating unit, wherein the substructure number calculating unit and the atom calculating unit calculate the numbers of substructures and the number of atoms from the generated model structure.