The authors propose a new technique for measuring fiber orientation in molded products by using anisotropic magnetic particles. The technique was applied to analyzing glass fiber orientation in NBr compounds, containing 5 wt% and 20 wt% glass-fibers, under repeated roll calendering. The validity of the technique was examined. Needle magnet particle of Co-gamma-Fe2O3 were mixed with the NBR compound. An orientation parameter S of the magnetic particles was defined. The distribution of the S value with the glass fiber orientation was compared by using Scanning Electron Microscopy. The good agreement confirmed the validity of this technique. Studies on the fiber orientation in compression and transfer molding were also conducted to demonstrate the applicability for the molding process. The distribution of fiber orientation was found to depend on the molding method. With compression molding the fiber orientation inside pre-molded materials was found to remain conspicuously. On the other hand, in transfer molding the orientation of fibers was found to start in the flow direction immediately after the gate.