A subject for the invention is to provide a method of transferring a polymerizable liquid by which the polymerizable liquid can be stably transferred without arousing any mechanical-seal trouble over long. The method of transferring a polymerizable liquid utilizes a pump which has a mechanical seal having seal faces and has a flushing liquid line for supplying a flushing liquid to a flushing liquid introduction opening of the mechanical seal, wherein the flushing liquid line is equipped with a strainer, a device for adding a polymerization inhibitor, or a flushing liquid cooler.