  We study the compositeness of near-threshold states to clarify the internal
structure of exotic hadron candidates. Within the framework of effective field
theory, we extend the Weinberg's weak-binding relation to include the nearby
CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade
approximant. Finally, using the extended relation, we conclude that the CDD
pole contribution to the Lambda(1405) baryon in the Kbar N amplitude is
negligible.
