A simulation method for flow of fluid around a body, according to the present invention, comprising dividing a target domain of simulation into a plurality of computational unit domains named cubes, generating an uniform number of Cartesian mesh elements named cells, in each of the cubes, performing computation in the cubes in each computational step, and exchanging data between adjacent cubes after completion of each computational step. In dividing the target domain of simulation into cubes, division is repeated while a ratio between adjacent cube sizes is maintained in a certain range until cubes including a boundary between the body and the fluid, is small enough to obtain a desired resolution so that sizes of the cubes are appropriately determined according to a shape of the body.