ove, and information including: [0045] (a???) the parasitic capacitance value of each node; and [0046] (b???) the size of a transistor driving the node; [0047] is put in order and a database including the information is formed. [0048] From the databases formed by these data extraction tools 40 and 40 a, a capacitance/size comparison tool 50 picks up the parasitic capacitances and the sizes of tran