A method for producing a needle-shaped body having needles on a first surface of a substrate made of a thermoplastic resin, the method including the steps of: forming the needle-shaped body by filling the thermoplastic resin into a duplication plate having recesses that correspond to shapes of the needles; providing a support member made of a material different from a material for the needle-shaped body on a second surface of the substrate which is opposite to the first surface; and removing the needle-shaped body and the support member which are integrally formed from the duplication plate.