A program generation method for generating a program which performs numerical simulation on a computer for a physical phenomenon by entering, to the computer, shape information of a spatial region in which the physical phenomenon takes place, conditions of numerical simulation including variables and constants necessary for the numerical analysis of the physical phenomenon, a partial differential equation using the variables and constants, and initial condition, boundary condition and material coefficient of the spacial region, and equation information including computational procedures. The formula information of an entered simulation model is analyzed to detect lacking information and the shape information of the simulation model is analyzed to detect parts, in correspondence to the shape information, in the spatial region in need of setting further equation information in addition to the first-mentioned equation information, and the detected lacking equation information and information of detected parts are analyzed in need of setting further equation information and the lacking equation information and the detected parts for which the lacking information is to be set are displayed, thereby prompting a user in an interactive manner to enter the lacking equation information, and a numerical simulation program is generated using the information of simulation model entered initially and supplementary equation information entered by the user.