Provided are a flexible thermoelectric generator, a wireless sensor node including the same and a method of manufacturing the same. The flexible thermoelectric generator includes a plurality of P-type semiconductors and a plurality of N-type semiconductors, which are alternately arranged, an upper metal for connecting upper surfaces of the adjacent P-type semiconductor and N-type semiconductor, a lower metal for connecting lower surfaces of the adjacent P-type semiconductor and N-type semiconductor, and alternately disposed with respect to the upper metal, a P-type metal connected to at least one P-type semiconductor among the plurality of P-type semiconductors, and an N-type metal connected to at least one N-type semiconductor among the plurality of N-type semiconductors.