The structure of the 10 Λ Be and 10 Λ B with an α+α+Λ+N four-body model cluster model is studied. The two-body ΛN interaction is adjusted so as to reproduce the 0+–1+ splitting of 4 Λ H. Also a phenomenological ΛN charge symmetry breaking (CSB) interaction is introduced. The ΛN CSB interaction works repulsively by +0.1 MeV (attractively by −0.1 MeV) in 10 Λ Be ( 10 Λ B). A neutron-rich Λ hypernucleus, 6 Λ H is studied within a framework of t+Λ+n+n four-body model. As long as we reproduce the energy and width of 5 H within the error bar, then ground state of 6 Λ H is obtained as a resonant state.