Microthermometry and micro-Raman spectroscopy are performed on fluid inclusions within lenticular quartz veins elongated parallel to the main foliation of a pelitic schist of the Sanbagawa metamorphic belt, Saganoseki, Kyushu, Japan. The fluid inclusions are isolated or are arranged along the planes, which are developed subparallel (similar to 20 degrees) to the main foliation of the quartz veins. Both types of fluid inclusions show similar homogenization temperatures and compositions in the H2O-NaCl-CH4 system. The trapping P-T conditions of the isolated fluid inclusions are determined to be 3.7-6.5 kbar and 320-450 degrees C by combining microthermometry and the pressure dependence of CH4 Raman shift. The estimated P-T range is consistent with the peak metamorphic conditions of the host rock (6-8 kbar, 300-400 degrees C) or bit lower, suggesting that the fluid inclusions are primary or secondary ones trapped at a relevant depth and they are potential evidence on the fluid composition derived from metamorphic reactions at 10-20 km depths.