A depressible key structure includes a key frame, a keycap, and plural elastic arms. The key frame has a receiving hole. The keycap is accommodated within the receiving hole, and includes plural outer corner portions. Each of the elastic arms includes an inner fixed arm part, at least one outer movable arm part, and a corner transition part interconnected between the inner fixed arm part and the at least one outer movable arm part. The corner transition parts of the elastic arms correspond to respective outer corner portions of the keycap. Each of the inner fixed arm parts is positioned at an inner edge of a specified side of a bottom surface of the keycap. A corresponding corner transition part is protruded out of the specified side to an adjacent side along a corresponding outer corner portion. The outer movable arm part is fixed on the key frame.