Pipetting device capable of accurately controlling filling amount

The utility model discloses a pipetting device capable of accurately controlling the filling amount. Negative pressure housing, second threaded rods are rotationally connected to the inner walls of one sides of the bottom and the top of the negative pressure shell through bearings; the second threaded rod extends to the outer part of the negative pressure shell; the outer wall of the circumference of the second threaded rod is sleeved with a piston through a thread; a limiting rod is inserted into the outer wall of one side of the top of the piston, a second fixing block is welded to the outer wall of the top of the second threaded rod, a third threaded rod is rotatably connected to the outer wall of one side of the top of the negative pressure shell through a bearing, a third fixing block is welded to the outer wall of the top of the third threaded rod, and a first gear sleeves the outer wall of the circumferential bottom of the third threaded rod. According to the pipetting device, the supporting rod, the f