Abstract: A micro adjusting device for lifting and lowering the worktable of a planer includes a base, a movable worktable positioned at one side of the base and having two fix holes in two side plates, and a micro-adjusting device positioned at one side of a connect rod of a connect rod device. The micro-adjusting device has a fix shaft pivotally connected to an upper portion. The fix shaft passes through the two fix holes of the movable worktable, enabling the worktable move up and down on the inclined surface of the base by means of the micro-adjusting device.