A safety anchor includes a fixed member to be securely fixed on a building frame in construction or to a side wall of a building and a removable member releasably engageable with the fixed member for supporting or protecting a person from falling out of the building or building frame. The fixed member has an expanded base to be welded to the steel structure or the steel bar of a reinforced concrete structure or buried in the concrete structure and a central bore to receive the insertion of the removable member. The removable member has a sideways projected key to be guided by a first slot formed on inside surface of the bore during the insertion of the removable member. The bore also has a circumferential slot formed on the inside surface-thereof and in connection with the first slot and a retaining slot that is also connected to the circumferential slot but spaced from the first slot so that it is capable to retain the removable member within the bore of the fixed member by moving the key through the circumferential slot to get into and trap in the retaining slot. A spring is provided within the bore to prevent accident release of the key out of the retaining slot. A cable is attached to the removable member for securing the a person or an article thereon.
