A lock device includes a cam portion including a stationary-side cam; a rotor including a movable-side cam; a slide groove; a slide projection; an engagement projection; and a lock groove, in which the movable-side cam is disengaged from the stationary-side cam, so that the rotor rotates so as to allow the engagement projection that has been fitted in the lock portion to disengage from the lock portion. The urging device includes a spring, and a sleeve inserted to pass through a lower-side rod portion, positioned between the rotor and the spring, and also restricting a movement of the rod in a sliding direction in a lock position of the lock device (for example, a lock groove and an engagement projection, and the like).