  We introduce a new polarimeter installed on the high-resolution fiber-fed
echelle spectrograph (called BOES) of the 1.8-m telescope at the Bohyunsan
Optical Astronomy Observatory, Korea. The instrument is intended to measure
stellar magnetic fields with high-resolution (R $\sim$ 60000)
spectropolarimetric observations of intrinsic polarization in spectral lines.
In this paper we describe the spectropolarimeter and present test observations
of the longitudinal magnetic fields in some well-studied F-B main sequence
magnetic stars (m_v < 8.8^m). The results demonstrate that the instrument has a
high precision ability of detecting the fields of these stars with typical
accuracies ranged from about 2G to a few tens of gauss.
