  Five-quark (5Q) picture of Lambda(1405) is studied using quenched lattice QCD
with an exotic 5Q operator of N\bar{K} type. To discreminate mere N\bar{K} and
\Sigma\pi scattering states, Hybrid Boundary Condition (HBC), a
flavor-dependent boundary condition, is imposed on the quark fields along
spatial direction. 5Q mass m_{5Q}\simeq 1.89 GeV is obtained after the chiral
extrapolation to the physical quark mass region, which is too heavy to be
identified with Lambda(1405). Then, Lambda(1405) seems neither a pure 3Q state
nor a pure 5Q state, and therefore we present an interesting possibility that
Lambda(1405) is a mixed state of 3Q and 5Q states.
