  We propose a method for searching dark matter axion in axion-photon
conversion. We consider a superconductor of cylindrical shape under strong
magnetic field. The dark matter axion generates oscillating electric field
which induces oscillating superconducting current in the surface of the
superconductor. The current gives rise to dipole radiation with the frequency
$m_a/2\pi$ given by axion mass $m_a$. We show that the radiation flux generated
by the current is of the order of $10^{-18}$W under magnetic field $\sim 3$T in
the case of radius $\sim 1$cm and length $\sim 10$cm of the cylindrical
superconductor. %The superconducting current flows in the surface to the depth
$\lambda\simeq 5\times 10^{-6}$cm. The large amount of the radiation flux
arises because Cooper pairs with large number density ( $\sim 10^{22}/\rm
cm^{3}$ ) is present in the superconductor. With the high detection
sensitivity, we can simultaneously search wide bandwidth of the radio frequency
with existing radio telescope.
