A test structure of a semiconductor device is provided. The test structure includes a semiconductor substrate, a transistor which includes a gate electrode formed on first and second active regions defined within the semiconductor substrate, and first and second junction regions which are arranged at both sidewalls of the gate electrode to reside within the first and second active regions and are silicided, and first and second pads through which electrical signals are applied to the silicided first and second junction regions and detected and which are formed on the same level as the gate electrode or the semiconductor substrate.