A key structure includes a keycap, a base plate, a first scissors-type connecting element, a second scissors-type connecting element and a reinforced connecting rod. The first and second scissors-type connecting elements are arranged between the keycap and the base plate. The first scissors-type connecting element includes a first inner frame and a first outer frame. The second scissors-type connecting element includes a second inner frame and a second outer frame. The keycap is movable upwardly or downwardly relative to the base plate along a specified path with the assistance of the first and second scissors-type connecting elements. The reinforced connecting rod includes a hollow rectangular main body. The first outer frame has a first extension structure. The second outer frame has a second extension structure. Moreover, two opposite sides of the hollow rectangular main body are respectively received within the first extension structure and the second extension structure.