Abstract: A chain saw guard including a substantially planar shield member pivotally supported to the rear end portion of the guide bar of the chain saw for pivotal movement alongside the chain bar between a lower guard position and an upper inoperative position, spring means urging the shield member downward into the guard position, latch means interconnecting the guide bar and the shield to lock the shield member in its guard position, and a downward projecting trigger element operatively connected to the latch means for releasing the latch means upon upward movement of the trigger element, such as by a log engaging the bottom of the chain saw.