A wiring substrate includes a base insulating film, a first
interconnection formed on a top surface side of the base insulating film,
a via conductor provided in a via hole formed in the base insulating
film, and a second interconnection provided on a bottom surface side of
the base insulating film, the second interconnection being connected to
the first interconnection via the via conductor. The wiring substrate
includes divided-substrate-unit regions, in each of which the first
interconnection, the via conductor, and the second interconnection are
formed.