Provided is a method of extracting a relational formula that relates two material property parameters from a textbook document using a computer and storing the extracted relational formula in a material property relationship database, which method enables search in consideration of a quantitative relationship between material properties. The information processing method according to the present invention comprises inputting a relational formula representing a relation between a pair of material property parameters in a material property relationship database storing pairs of mutually related material property parameters. Equation information representing a relational formula is extracted from read input data, and multiple variables constituting a relational formula and a relational formula specifying that relation are extracted from the equation information. Description defining each of the extracted variables is extracted from the input data, and each variable is associated with a material property parameter with reference to the material property relationship database. The extracted relational formula is input in the material property relationship database in association with the pair of material property parameters corresponding to two of the multiple variables constituting the relational formula.