A design aid apparatus includes an input section, an antenna propensity determination section, an output section, and a memory storing design data for a plurality of structures comprising an electronic device to be designed. Conductivity of a structure is determined based on conductivity information of the structure read out from the memory. The antenna propensity determination section determines a contact relation, which expresses a state of electrical contact between a conductive structure having conductivity and another conductive structure, based on information relating to shapes and arrangements of structures stored in the memory. A length of a route between a reference conductive structure and the conductive structure is determined. The antenna propensity of the electronic device is evaluated based on the route length.