Abstract: A method of and apparatus for performing error estimation for a computational fluid dynamic analysis, which quantitatively indicates an error involved in the computational solutions. Virtual substance advection calculation means performs an advection computation, assuming that a virtual substance whose diffusion coefficient is substantially zero is mixed in the fluid, wherein the behavior of the fluid is given by flow field data that is previously obtained as a result of the computational fluid dynamic analysis. Through the advection computation, the virtual substance advection calculation means obtains concentration data of the virtual substance, thus allowing an error in the flow field data to be estimated by comparing the concentration value after advection of the virtual substance with its initial value. If the flow field data perfectly satisfies the primitive equations of fluid dynamics, the concentration value of the virtual substance will not vary with advection.