PURPOSE: To reduce the burden on a designer and to improve the efficiency of designing as to the design assistance system which is used to design the semiconductor device.

CONSTITUTION: Pad coordinate information and chip shape information are read out of, for example, a storage file 11, bonding die attachment standard information is read out of a data base 12 for storage, and an inner lead bonding coordinate information determination part 13 determines inner lead bonding coordinate information according to those pieces of information. Then a frame design part 14 designs a lead frame on the basis of the inner lead bonding coordinate information. A standard decision part 15 decides whether or not frame shape data on the designed lead frame satisfies respective pieces of condition information of the bonding die attachment standard information to decide whether or not the semiconductor is properly designed.