1H-NMR investigation was carried out for the metallic state of α-(BEDT-TTF) 2 I 3 stabilized at a high-pressure of 15 kbar. The spin-lattice relaxation rate, T 1 - 1 , is almost temperature independent below 50 K when the external magnetic field, H 0 , is applied exactly parallel to the conducting plane. For H 0 perpendicular to the plane, a peak-like enhancement of T 1 - 1 was observed at around 10 K. It is obviously related to the field induced phase observed in resistivity measurements.