An objective is to provide a method of forming a piezoelectric resin film produced at low cost, and specifically to provide the method in which a large-area piezoelectric resin film is produced at low cost, and at reduced investment in facilities. Disclosed is a method of forming a piezoelectric resin film possessing the steps of polymerizing a monomer at a temperature of 5-60° C. to obtain a resin having a polymerization degree of 4-300, and a polarity group possessing one bond selected from a urea bond, an ester bond, an amide bond and an imide bond, coating the resin onto a substrate; and further polymerizing the resin at 70-250° C. while conducting a poling treatment.