The method of producing a transdermal absorption sheet includes, in this order, a filtration step of carrying out sterile filtration on a base liquid, a base liquid feeding step of feeding the base liquid to a surface of a mold having needle-like recessed portions, tip ends of which are filled with a drug solution, while leaving a space between the drug solution and the base liquid, a drying step of drying the drug solution and the base liquid, and a peeling-off step of peeling off a formed transdermal absorption sheet in which an average concentration of solid contents of the base liquid in the drying step is increased by 5% by weight or more from an average concentration in the base liquid feeding step, and then in a state in which the average concentration is 75% by weight or less, the base liquid is moved into the needle-like recessed portions.