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Phase diagram and critical exponents of an extended Kagome' XY model is studied. With antiferromagnetic nearest-neighbor interactions J₁, the model is characterized by O(2) spin rotaton symmetry as well as Z₂ symmetry due to spin chirality at low temperatures. By introducing second-neighbor interactions J₂, O(2) x Z₂ symmetry breaking is observed in the ground state. Using Monte Carlo calculations, we investigated  spin O(2) transition (BKT) and chirarity Z₂ phase transitions at finite temperatures, where complex interplay between these continuous and discrete degrees of freedom are expected. Transition temperatures are estimated as a function of the interaction ratio J₂/J₁. We discuss whether these transitions occur simultaneously or successively, by comparing critical exponents for spin and chirality sectors with those estimated by the conformal field theory.