Provided are a differential inductor and a semiconductor device including the same, the differential inductor including first circular parts and second circular parts disposed on a first layer and composing a first spiral shape, a first semi-circular part disposed on the first layer and in the first circular part that is an innermost one of the first circular parts, and a second semi-circular part disposed outside the first circular part that is an outermost one of the first circular parts, third semi-circular parts and fourth semi-circular parts disposed on a second layer under the first layer and composing a second spiral shape, connection means configured to connect, to one, the first and second circular parts, and the first to fourth semi-circular parts, wherein the second circular parts are respectively interposed between the first circular parts, and a part of the fourth semi-circular parts is respectively interposed between the second semi-circular parts.