The inventive concept provides optical switch devices and methods of manufacturing the same. The optical switch device may include a substrate including a first region and a second region, a first multi-mode optical waveguide disposed on the substrate of the first region, an electrode wire disposed on the substrate of the second region, a heater disposed on a top surface of the first multi-mode optical waveguide, and connection wires connecting the heater to the electrode wire. The first multi-mode optical waveguide may have incline sidewalls, and the connection wires may be disposed on the incline sidewalls of the first multi-mode optical waveguide.