A stencil is made by thermally forming perforations arranged in both a main scanning direction and a sub-scanning direction in a thermoplastic resin film of heat-sensitive stencil material by the use of a heat source which is heated through supply of energy. Supply of energy to the heat source is cut when a time interval not shorter than 50% and not longer than 100% of an estimated perforating time lapses from the time at which supply of energy to the heat source is started. The estimated perforating time is a time interval expected to be necessary for a perforation to be produced by the heat of the heat source and to be enlarged to a desired size as a final size as measured from the time at which supply of energy to the heat source is started.