A lock structure for an electrical device includes a rotatable fastener and a lock body. The rotatable fastener has an extending portion and a retaining portion, wherein the extending portion and the retaining portion form a T-shaped structure; the lock body is connected to the rotatable fastener and has a key hole. The lock body further has a first position and a second position in a radial direction of the extending portion. The key inserted in the key hole operates the lock body to displace from the second position to the first position, wherein the lock body drives the rotatable fastener to rotate to an unlocked position. When the lock body is in the first position, the lock body is pressed to displace from the first position to the second position, wherein the lock body drives the rotatable fastener to rotate to a locked position.