Abstract: In a database, variety of modules which can be used as constituent elements of the object of design are registered as parametrized models, and instance generating information representing a procedure of generating instances and feature estimation information representing a method for estimating design features are stored every abstraction level for the various modules. A floorplan oriented design is executed by means of the database. That is, even at the higher level of the behavior or RT level, by means of the database, the design features of each module to be used for the design are estimated and the floorplan is executed. On the basis of the execution result, the design features of the circuit scale, delay time, power consumption and so forth of the object of design are estimated, and it is decided whether or not a design change is required.