A key structure includes a base plate, a position-limiting structure, a stabilizer bar and a keycap. The position-limiting structure is connected with and fixed on the base plate. A slot is defined by the position-limiting structure and the base plate. The stabilizer bar is connected with the keycap and pivotally coupled to the slot. The position-limiting structure includes a top stopper. The top stopper is made of soft material. As the stabilizer bar is rotated and the stabilizer bar is contacted with the top stopper, the efficacy of reducing noise is enhanced.