A semiconductor device includes a wiring substrate including a first surface, a second surface opposite to the first surface, a first heat dissipation conductive pattern formed on the first surface, a second heat dissipation conductive pattern formed on the first surface, a first wiring formed on the first surface, and a second wiring formed on the first surface. The semiconductor device also includes a semiconductor chip disposed on the wiring substrate and including a third surface and a fourth surface opposite to the third surface. In plan view, the second wiring is adjacent to the first and second heat dissipation conductive patterns without intervening any wiring and any conductive pattern between the second wiring and the first and second heat dissipation conductive patterns.