A parameter design assistance device (2) includes storage (24) and a controller (25). The storage (24) stores therein a recipe for controlling a substrate processing device (81). The controller (25) acquires one or more level values for each of control factors. The level values indicate conditions according to which the substrate processing device (1) is to process a substrate (11). The controller (25) generates, through statistical technique, combination information representing combinations of the level values acquired. The controller (25) creates an evaluation recipe for each of the combinations of the level values based on the combination information and the recipe stored in the storage (24). When the evaluation recipe includes a parameter corresponding to a control factor, the controller (25) sets a corresponding level value for the control factor as a parameter value of the parameter.