A locking device includes a body, a first part, an engaging assembly, a link and a locking member. The body has an installation area and the engaging assembly is installed in the installation area and includes a first engaging member and a first resilient member which provides a force to the first engaging member to connect the engaging member to the first part. The link is movably located in the installation area to push the first engaging member to move relative to the first part to release the locked status. The locking member is located in the installation area and has a first recess and an operation end. When the first recess is located corresponding to the first engaging member, the first engaging member is movable in the first recess. When the first recess is located away from the first engaging member, the first part is secured to the body.