  In order to investigate whether space coordinates are intrinsically
noncommutative, we make use of the Hall effect on the two-dimensional plane.
  We calculate the Hall conductivity in such a way that the noncommutative U(1)
gauge invariance is manifest. We find that the noncommutativity parameter theta
does not appear in the Hall conductivity itself, but the particle number
density of electron depends on theta.
  We point out that the peak of particle number density differs from that of
the charge density.
