Fuel physical property

Patent Pending PROBLEM TO BE SOLVED: To more easily determine a fuel physical property (octane number). ; SOLUTION: The fuel physical property determination method includes a reaction mechanism analysis step S1 for acquiring fuel elementary reactions, by analyzing the elementary reactions constituting the chemical reactions among a plurality kinds of initial materials containing materials composing the fuel, and an octane number determination step S2 for determining the octane number by calculating combustion characteristics of the fuel by performing a simulation, based on the fuel elementary reactions, and based on the combustion characteristics of the fuel