Provided is a method of producing a transdermal absorption sheet using an electroforming mold. A method of manufacturing an electroforming mold includes preparing a mold which is a matrix having a recessed pattern, immersing the mold in a degassed pretreatment liquid stored in a pretreatment liquid tank, then applying ultrasound waves generated from an ultrasound oscillator to the recessed pattern of the mold, and filling recessed portions constituting the recessed pattern with the pretreatment liquid. By immersing the mold in an electroforming tank and performing an electroforming treatment, an electroforming mold is manufactured. A mold having a recessed pattern is manufactured from the electroforming mold and a transdermal absorption sheet is produced using the mold.
