A gas flow simulation method includes setting an imaginary object model such as a sphere model having at least one concavity, convexity, groove or projection formed thereon by means of a computer. A spatial part on a periphery of the imaginary object model is set. A surface of the imaginary object model and the spatial part is divided into a large number of blocks to form a large number of latticed divisions by lattice points. A gas flows to the imaginary object model from one direction of the spatial part. A motion element of a flow of the gas in the spatial part for each latticed division or for each latticed point is computed, with the gas flowing in the spatial part and passing along the surface of the imaginary object model. The flow of the gas on the periphery of the imaginary object model is simulated.