Inhomogeneous structure in natural rubber (NR) vulcanizate was examined by ¹H pulsed NMR. The spin-spin relaxation times (T₂) under various extension ratios (α) were measured by the Hahn echo method and the solid echo method. The decay curves of NRs were resolved into three T₂ components, T_2SS, T_2HS, and T_2HL, which were respectively arising from the strain-induced crystalline chains, the network chains, and the more mobile chains that were less affected by crosslinks or entanglements. T_2HS and T_2HL decreased with increasing α. However, T_2HL leveled off at α beyond 4 while T_2HS kept decrease. The decrease in T_2HL with α was more rapid than that of T_2HS until T_2HL became constant. This indicates that the deformation of the more mobile chains was larger than that of the network chains. The increase in the fraction of T_2SS component with increasing α was observed in the region of α that T_2HL were almost unchanged. It was suggested that the strain-induced crystallization is closely related with the more mobile chains.