Abstract: A liquid flow measuring device for lubrication systems and the like allows liquid flow measurement to be made with a minimum interruption of liquid flow and no dismantling of lubricant pipes to lubricated elements. The measuring device comprises a container body having a liquid inlet and a liquid outlet for discharging from a lower portion of the body to an outlet line, the body having a transparent side such that liquid level within the container body is visible with a low level mark and a high level mark. The liquid is temporarily prevented from discharging from the outlet of the body, but the liquid is allowed to flow through the inlet of the body so the liquid level rises from the low level mark to the high level mark.