To provide a lock device capable of easily opening a door in an emergency.

A lock device 11 includes: an escutcheon 27 having an interior space 31 and rotatably supporting a basic shaft 39 of an operation member by being fixed on a door surface; a restriction body 29 of which a button part 99, which is supported by an oscillation shaft 83 parallel to the door surface in the interior space 31 in a free oscillating manner so as to be integrally fixed, is protruded outward from a button opening hole 97 of the escutcheon 27, and in which an engaging part 75, which protrudes inside the interior space 31 in the same direction with the button part 99, is provided; and a lock plate 55 of which front and rear surfaces are fixed in an orthogonal direction to the basic shaft 39 penetrating through the interior space 31 and in which an engaged part 69 regulating the rotation of the basic shaft 39 by engaging the engaging part 75 is formed.