A keyswitch device includes a supporting seat, a key cap, a circuit board disposed on the supporting seat, and an elastic member located between the key cap and the circuit board. The supporting seat includes a base board and two first confining members that are formed on the base board and that are spaced apart from each other. The key cap includes a cap body and two first hooks that engage respectively the first confining members, thereby inhibiting the key cap to move in horizontal directions with respect to the supporting seat, and allowing the key cap to move vertically in a range equal to the height of the first blocking parts of the first confining members. When the key cap is moved downward, the elastic member deforms to press the circuit board so as to generate a corresponding signal.