A thermoelectric device according to an embodiment of the present invention comprises: a first substrate; an insulating layer disposed on the first substrate; a first electrode unit disposed on the insulating layer; a first terminal electrode and a second terminal electrode disposed on the insulating layer and protruding from the first electrode unit toward the first outer side of the first substrate; a semiconductor structure disposed on the first electrode unit; a second electrode unit disposed on the semiconductor structure; and a second substrate unit disposed on the second electrode unit. The second substrate unit comprises a plurality of second substrates disposed away from one another. The first electrode unit comprises: a plurality of electrode groups respectively overlapping the plurality of second substrates vertically; and a first connection electrode connecting two different electrode groups among the plurality of electrode groups. The long side of the first connection electrode is longer than the long side of the first electrode included in the plurality of electrode groups. At least a part of the first connection electrode does not overlap the plurality of second substrates vertically.