Application of polarization proton scatterings to radioactive nuclear beam experiments is proposed. A polarized proton solid target which works at a high temperature of several tens of Kelvin and in a low magnetic field of ∼ 0.1 T is needed for the purpose. The proton polarization can be produced by transferring an electron population difference in photo-excited triplet states of an aromatic molecule by means of a cross polarization technique. By using this method, we have constructed a polarized proton solid target specifically designed for use in radioactive nuclear beam experiments. The target has been used in the measurement of vector analyzing power for the p - 6He elastic scattering at 71 MeV/A.