PURPOSE: To visually express the forming state of a shadow cone by overlappingly displaying the shadow cone based on the data of ion incidence conditions or the like on the coupling model display of atoms based on molecular structure data.

CONSTITUTION: The coaxial direct collision ion scatter by ions accelerated at a low speed is simulated, the scattering phenomenon is displayed and the positions of surface atoms are determined. The atom coupling model is displayed on a display unit 3 by the first display controller 2b based on the molecular structure data about the positional relation of constituting atoms of a sample from an input device 1 in this ion scatter display device. The formed state of a shadow cone is obtained by a data processing arithmetic section 2a based on the data such as the element species, incident ion species, incidence energy, and incidence angle from the input device 1. The shadow cone is overlappingly displayed on the atoms on the model surface displayed on the display unit 3 by the second display control device 2c, and positional relation is set in response to the incidence angle.