The aim of this paper is to show that the vector potential in the so-c
alled Aharonov-Bohm (A-B) effect is not a gauge transformation of the
vacuum, even when alpha = integer(not equal 0) (where alpha = Phi/Phi(
0) represents the magnetic flux in the long cylindrical solenoid and P
hi(0) = h/e). To this end, it is discussed that the wave function of t
he electron and the gauge function in a gauge transformation are requi
red to be single-valued so that the Schrodinger wave mechanics and the
Maxwell electromagnetic theory are well-formulated. It is also discus
sed that the gauge transformation of wave functions and the representa
tion change of operators of Kobe's meaning are the same thing.