  We present the first 6.7 GHz methanol maser linear polarization map of the
extended filamentary maser structure around the compact HII region W3(OH). The
methanol masers show linear polarization up to 8 per cent and the polarization
angles indicate a magnetic field direction along the North-South maser
structure. The polarization angles are consistent with those measured for the
OH masers, taking into account external Faraday rotation toward W3(OH), and
confirm that the OH and methanol masers are found in similar physical
conditions. Additionally we discuss the Zeeman splitting of the 6.7 GHz
methanol transition and present an upper limit of ~22 mG for the magnetic field
strength in the maser region. The upper limit is fully consistent with the
field strengths derived from OH maser Zeeman splitting.
