  We present the recent progress in the study on the origin of baryon
resonances in chiral dynamics. It is shown that in the chiral coupled-channel
approach, the form of the interaction cannot be specified due to the cutoff of
the loop integral. To avoid this ambiguity, we propose a natural
renormalization scheme, which affords a clue to the origin of the resonance,
together with the phenomenological fitting to experimental data. We study the
structure of the Lambda(1405) resonance in comparison with the N(1535).
