Abstract: Microneedle sheets are produced by injecting a needle raw material into a stamper formed with a concavity in a base material. However, because the stamper concavity is very small, there is the problem that air cannot escape due to air and surface tension of the material, thereby preventing a needle from being formed in part. The present invention provides a stamper for producing a microneedle sheet. The stamper comprises a sheet-like base material including a conical concavity formed from a first surface of the sheet-like base material toward a second surface thereof; and a through-hole formed from a bottom of the concavity toward the second surface. Air can escape via this through-hole, allowing a microneedle sheet which is filled with a needle raw material as far as the bottom of the concavity to be obtained.