  We investigate Lambda(1405) as a resonance in a coupled channel baryon-meson
scattering with a `bound state embedded in the continuum'(BSEC). This BSEC is
introduced by hand, as a state not originated from simple baryon-meson systems.
We assume it comes from the three-quark state.
  There appears a resonance in the Sigma pi scattering below the N Kbar
threshold when the N Kbar channel is taken to be strongly attractive. It occurs
without introducing a BSEC, just like the chiral unitary approach. When a BSEC
is introduced, a resonance also appears with a weaker baryon-meson interaction.
The corresponding peak also has a large width, and the N Kbar scattering length
is reproduced well. The interaction whose channel dependence is the same as the
one originated from the color-magnetic interaction, where no N Kbar attraction
exists, also gives a broad peak like Lambda(1405) with help of a BSEC.
  It is found that the BSEC coupling which does not vanish at the zero momentum
transfer give a larger width. In order to reproduce the observed N Kbar
scattering length, introducing a BSEC seems preferable. In our calculation, a
model gives an appropriate value when the BSEC contribution to the resonance is
roughly half of that of the N Kbar in size.
