An input device includes at least one key structure and a film circuit board disposed below the key structure. The key structure includes a top cover, a plunger, a sleeve, a rod, a first elastic element, a second elastic element and a bottom cover. The plunger is assembled on the top cover and has a protruding portion protruding from a first opening of the top cover and a guiding portion. The sleeve is assembled inside the plunger. The rod is movably disposed in the sleeve. The first elastic element is disposed in the rod, wherein the guiding portion passes through the first elastic element so that a first end of the first elastic element leans against the plunger. The bottom cover having a second opening locks the top cover. A second end and a third end of the second elastic element respectively lean against the sleeve and the bottom cover.