Poly(L-lactic acid) (PLLA) gels were formed by complex crystals (epsilon-crystals) with some solvents, such as N,N-dimethylformamide (DMF), and the solvent in the gel was exchanged to other solvents, such as water, by the immersion of the gel into the solvent. Although X-ray diffraction patterns of the gels indicated that the epsilon-crystals formed in DMF changed to alpha-crystals, the structure formed by spherulites observed by polarizing microscopy showed no change by the solvent exchange. The gelation mechanism was proposed based in the experimental data.