Abstract: A locking device for use with a combined handle and rotary latch assembly having a latching hook mounted on an axle stud that is journaled for rotation, in a latch assembly, comprising a locking slide disposed alongside the stud and having a keyhole recess receiving an elongated tab on the end of the axle stud, the recess having a narrow channel portion which slides over the tab in close fitting relation to lock the latch, and having an enlarged circular portion in which the tab can rotate without restriction, to unlock the latch. Yieldable detents restrict motion of the slide from locked to unlocked positions. In one embodiment, the slide is a one-piece molding with a shaped locking recess inside an operating knob, and in another embodiment, a separately formed nylon insert is fitted in the body of the slide to form the locking parts.