To provide a lock device which can be retained in an unlocked state compared with an existing device and can prevent lockout when a sliding screen is closed without operating a handle.

In the lock device 20, unless the handle 35 is operated, rotation of a pole 43 is regulated by abutting a second rotation regulation lever 45A on a second rotation regulation face 43W for preventing lockout. Even when the abutment of the second rotation regulation lever 45A on the second rotation regulation face 43W is insufficient due to variation in machining shapes of components, a first rotation regulation lever 42B runs on a clearance-forming projection 42X arranged on a first rotation regulation face 43V while a latch 42 rotates from a disengaging position to an engaging position and a clearance C1 is formed between the second rotation regulation lever 45A and the second rotation regulation face 43W so that the second rotation regulation lever 45A is moved to the position sufficient enough to abut with the second rotation regulation face 43W.