Drug concentration diluting device

The utility model relates to the technical field of medical instruments, in particular to a medicine concentration diluting device which comprises a liquid medicine storage tank, a diluent storage tank, a stirring tank, a liquid medicine extracting device and a diluent extracting device. Liquid medicine can be pumped into the negative pressure cavity of the liquid medicine injection cylinder by increasing the volume of the negative pressure cavity of the liquid medicine injection cylinder, the first valve body is closed, the second valve body is opened, the first piston is driven by the first driving mechanism to move, the volume of the negative pressure cavity of the liquid medicine injection cylinder is reduced, and the liquid medicine in the negative pressure cavity of the injection cylinder can be injected into the stirring cavity. The liquid medicine does not need to be manually added into the stirring tank, the risk that the liquid medicine spills out in the process that the liquid medicine is manually