A printed wiring board is made of first and second substrates superimposed
on each other. The first and second substrates respectively include a
core layer made of resin containing carbon fibers. The second substrate
has the outline different from that of the first substrate. A stepped
surface is defined on the front surface at least of the first substrate.
Electrodes can be formed on the stepped surface as well as on the back
surface of the first substrate and the front surface of the second
substrate. This structure enables detection of an electric signal from
the stepped surface. A further flexibility can thus be achieved in
locating electrodes as compared with a conventional printed wiring board
having uniform substrates simply superimposed on each other. This results
in an expanded use or purpose for a printed wiring board.