This invention provides a
molecular simulation method for quickly calculating the equilibrium density of a first
molecular model, which is modeled as an all-
atom model, and at least one of the terminal distance and
radius of
inertia. [Solution] The
molecular simulation method includes an equilibrium state calculation step which includes a step S11 of inputting a plurality of first molecular models that model the first molecule as an all-
atom model, a step S12 of inputting a second
molecular model that model the second molecule as an all-
atom model, a step S13 of inputting a mixed
system model that includes a plurality of first molecular models and second molecular models, and a step S14 of calculating the equilibrium state of the mixed
system model, and a density
estimation step which calculates at least one of the terminal distance and
radius of
inertia of the first molecular models in the equilibrium state mixed
system model, and estimates the equilibrium density of a system that includes only the first
molecular model based on the equilibrium density of the second molecule, the
mass of the first molecular model, the
mass of the second molecular model, and the volume of the mixed
system model in the equilibrium state.