Polarimetry is a unique tool for studying the physical processes in the
interstellar medium, including star-forming regions. However, it has
been much less explored than conventional photometry and spectroscopy.
Infrared polarimetry of young stellar objects and their circumstellar
structures provides very valuable information about the distribution of
matter of young stellar objects and the configuration of magnetic fields
within molecular clouds. Compared with linear polarization (LP), only a
few near-infrared circular polarization (CP) observations were reported
so far (before our survey). I have conducted a first systematic
polarization survey of star forming regions in both LP and CP. In this
presentation, I present our investigation for roles of magnetic fields
in cluster formation using linear polarimetry as well as new information
of magnetic and scattering fields obtained by the circular polarimetry
survey.