  The binary X-ray pulsar A0535+262 was observed with the Suzaku X-ray
observatory, on 2005 September 14 for a net exposure of 22 ksec. The source was
in a declining phase of a minor outburst, exhibiting 3--50 keV luminosity of
about $3.7 \times 10^{35}$ ergs s$^{-1}$ at an assumed distance of 2 kpc. In
spite of the very low source intensity (about 30 mCrab at 20 keV), its electron
cyclotron resonance was detected clearly with the Suzaku Hard X-ray Detector,
in absorption at about 45 keV. The resonance energy is found to be essentially
the same as those measured when the source is almost two orders of magnitude
more luminous. These results are compared with the luminosity-dependent changes
in the cyclotron resonance energy, observed from 4U 0115+63 and X 0331+53.
