A key testing apparatus (100) is provided. The key testing apparatus includes a base (11) and an actuator (12). The actuator includes a testing member (17) and a mounting member (18). The mounting member includes at least one base board (181) fixed to the base, a lower board (182), a mounting board (183), and a mounting sheet (185). The lower board is adjustably attached to the base board. The mounting board is adjustably attached to the lower board. The mounting sheet is adjustably attached to the mounting board. The clamping device includes a base desk (131), a clamping platform (132), at least one first clamping board (133) and second clamping board (134). The base desk is adjustably attached to the base. The clamping platform, at least one first clamping board, and at least one second clamping board are adjustably attached to the base desk.