Geometrically frustrated magnets have attracted great interest because of their exotic orders at low temperatures. In case of classical Kagome Heisenberg antiferomagnet its highly-frustrated geometry causes macroscopic degeneracy and a coplanar 120° structure is realized by order-by-disorder mechanism. In real compounds small perturbations make drastic change in the eigenstates at low energies and a novel magnetic state is induced. NaBa2Mn3F11 is a new model compound for Kagome lattice antiferromagnet. The crystal structure is hexagonal and the space group is R-3c. Mn2+ ion carries spin S = 5/2 and the MnF7 pentagonal bipyramids form a Kagome lattice in the c plane. A remarkable difference from conventional Kagome lattice is found in the unusual exchange pathway of the 2nd neighbor interaction J2.　Therefore it is expected to realize intriguing magnetic structure in NaBa2Mn3F11.