A key structure of a keyboard device includes a scissors-type connecting member and a base plate. The base plate includes a base plate fixing hook, a base plate sliding hook and a stopping structure. The entrance of the base plate fixing hook and the entrance of the base plate sliding hook face the same side. Due to the configurations of the base plate, the scissors-type connecting member can be easily assembled within the base plate fixing hook and the base plate sliding hook. In addition, the scissors-type connecting member can be fixed on the base plate by using the base plate fixing hook and the stopping structure.