Microneedle sheets are produced by injecting a needle raw material into a stamper formed with a concavity in a base material. However, it was not easy to increase the degree of sharpness of the concavity which corresponds to the stamper tips. A method for producing a stamper including the steps of heating a sheet-like base material and an original plate having a conical protrusion, inserting the protrusion of the original plate into the base material to form a conical concavity in the original plate, cooling the original plate with the original plate still inserted in the base material, releasing the original plate from the base material, and heating the base material.
