To manufacture a precise false nail chip which lessens the time and labor required for manufacture and comes into tight contact with the nail surface by forming a resin cured false nail chip, which is formed by packing a thermal polymerization type resin into a cavity and curing the resin by thermal polymerization, taking the nail chip out of a gypsum mold and subjecting the surface and front end thereof to shaping and finishing.

A flask upper ring 40 is opened and a resin separator is applied to the inside of the cavity 41 formed on the nail portion 34 on the fingertip gypsum pattern 33 for the false nail chip 43 of a flask lower ring 39. The thermal polymerization type resin 42 formed like dough is then packed into the cavity and is lightly pressed down and spread on the nail portion 34 (g). The flask is then closed and the flask is heated and held to and at a thermal polymerization temperature. The thermal polymerization type resin 42 inserted into the cavity 41 is polymerized and cured by heating, by which the cured false nail chip 43 is formed (h). The flask is then opened and the formed resin cured false nail chip 43 is taken out. The surface and front end thereof are subjected to shaping and finishing, by which the false nail chip is formed (i).