The chain end of poly(epsilon-caprolactone) was spin-labeled to study the molecular mobility of the polymer chain in an amorphous region under the crystallization. Time-resolved ESR measurements were carried out in the crystallization process. The three stages of the time evolution of the molecular mobility at the crystallization temperatures were found; the correlation time, tau(c), of the polymer chain increased gradually at the early stage and remarkably at the late stage. At the final stage, the tau(c) increased gradually again. The early stage is the induction period where no change of the scattering intensity is observed by the time-resolved SAXS and WAXS measurements. The gradual decrease of the molecular mobility is caused by the precursory aggregation of the polymer chain before the crystallization. At the late stage, the crystalline grows and the molecular mobility in the amorphous region becomes remarkably restricted by the rigid chains in the crystalline regions. At the final stage, the gradual decrease of the molecular mobility by the late growth of the crystalline observed again, where no structural change was detected by the measurements of X-ray scatterings.