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 .