A thermoelectric device is provided. The thermoelectric device includes a P-type thermoelectric component, an N-type thermoelectric component, and an electrically conductive layer. Each of the P-type thermoelectric component and the N-type thermoelectric component includes a substrate and a nanowire structure. The conductive layer connects the P-type thermoelectric component set with the N-type thermoelectric component set. The thermoelectric device is adapted for recycling heat generated by the heat source, and for effectively converting the heat into electrical energy.