A three-dimensional simulation apparatus includes a memory configured to store form information of a sheet flexible object model formed of first polygons and another object model, an interference determination unit configured to determine whether the sheet flexible object model formed of the first polygons in three-dimensional simulation space interferes with the other object model on the basis of the form information stored in the storage unit, a polygon creation unit configured to form second polygons by dividing the sheet flexible object model in a longitudinal direction when it is determined that the sheet flexible object model interferes with the other object model, and a shape computation unit configured to determine a shape of the sheet flexible object model using the formed second polygons in consideration of a shape of the other object model.