If the E-B analogy, which is current in the present theory of electromagnetism, is perfect, it seems to be natural that some magnetic material must exist that keeps the interior magnetic flux density B zero, corresponding to a conductor that keeps its interior electric field E zero. This is in fact a superconductor, which really exists. Hence, if someone would have assumed the existence of such a magnetic material based on this analogy in the nineteenth century, he would have predicted the superconductor, since it is possible to show that the electric resistivity of this material must be zero using Maxwell’s theory. The magnetic phenomena exhibited by superconductors correspond to electric phenomena exhibited by conductors in various aspects, including this point. In this chapter it is shown that introduction of the magnetic phenomena of superconductors into electromagnetism is inevitable if we wish to make the E-B analogy more rigorous. In addition, a quite unique magnetic phenomenon is introduced involving a transport current in a superconducting transmission line, which shows an example of the diverse phenomena that arise in nature due to the existence of superconductors. Reference (Electricity and magnetism—new formulation by introduction of superconductivity, 2nd edn. Springer, 2022 [1]) covers the topical area in this chapter.