A lock device for a vehicle comprising: a base plate fixed to one of a fixed member and a movable member and provided with an entrance/retracting groove for receiving or retracting a striker fixed to the other of the fixed member and the movable member; a latch pivotally supported on the base plate by a latch axis, the latch having a lock groove engaging with or disengaging from the striker entering the entrance/retracting groove and rotatable between a lock release position allowing the striker entering into the entrance/retracting groove and a lock position for holding the striker in the entrance/retracting groove by the movement of the striker; a pawl rotationally supported on the base plate at a pawl axis arranged apart from the latch axis for keeping the pawl to a lock releasable position for allowing the latch to be returning to the lock release position in a rotational range of the latch from the lock release position to the lock position and preventing the latch to return to the lock release position by the latch engaging with the pawl rotating to a release preventing position after the latch having been rotated to the lock position; a rotation lever rotationally supported on the base plate in association with the pawl; a rotation plate rotationally supported on the base plate coaxially with the latch axis and being rotated in a direction same with the rotation direction of the latch towards the lock position by engaging with the rotation lever upon the pawl being rotated from the release preventing position to the lock releasable position; a thrust plate connecting the rotation plate and a guide portion provided on the base plate and having an inclined cam surface extending in a crossing direction of the striker entering direction adjacent a bottom surface of the entrance/retracting groove and loosely supported on the base plate through the guide portion and moving the inclined cam surface into the entrance/retracting groove by connecting the thrust plate with the guide portion provided on the base plate to secure the striker between the inclined cam surface and the latch; a first biasing means (35, 43) for biasing the latch in the rotational direction to the lock release position and for biasing the pawl in a rotational direction towards the release preventing position; and a second biasing means for biasing the rotation plate in a rotational direction towards the lock release position of the latch. a base plate fixed to one of a fixed member and a movable member and provided with an entrance/retracting groove for receiving or retracting a striker fixed to the other of the fixed member and the movable member; a latch pivotally supported on the base plate by a latch axis, the latch having a lock groove engaging with or disengaging from the striker entering the entrance/retracting groove and rotatable between a lock release position allowing the striker entering into the entrance/retracting groove and a lock position for holding the striker in the entrance/retracting groove by the movement of the striker; a pawl rotationally supported on the base plate at a pawl axis arranged apart from the latch axis for keeping the pawl to a lock releasable position for allowing the latch to be returning to the lock release position in a rotational range of the latch from the lock release position to the lock position and preventing the latch to return to the lock release position by the latch engaging with the pawl rotating to a release preventing position after the latch having been rotated to the lock position; a rotation lever rotationally supported on the base plate in association with the pawl; a rotation plate rotationally supported on the base plate coaxially with the latch axis and being rotated in a direction same with the rotation direction of the latch towards the lock position by engaging with the rotation lever upon the pawl being rotated from the release preventing position to the lock releasable position; a thrust plate connecting the rotation plate and a guide portion provided on the base plate and having an inclined cam surface extending in a crossing direction of the striker entering direction adjacent a bottom surface of the entrance/retracting groove and loosely supported on the base plate through the guide portion and moving the inclined cam surface into the entrance/retracting groove by connecting the thrust plate with the guide portion provided on the base plate to secure the striker between the inclined cam surface and the latch; a first biasing means (35, 43) for biasing the latch in the rotational direction to the lock release position and for biasing the pawl in a rotational direction towards the release preventing position; and a second biasing means for biasing the rotation plate in a rotational direction towards the lock release position of the latch.