Abstract: A processing method and apparatus using a focused energy beam for conducting local energy beam processing in a focused energy beam irradiating area by irradiating a sample with a focused energy beam such as an ion beam or an electron beam in an etching gas atmosphere. As the etching gas, a mixed gas different in composition from any conventional one is employed and the gas is uniformly supplied to an etching area and at least one of the components of such a mixed gas is a spontaneous reactive gas for use in etching the sample spontaneously and isotropically. With this arrangement, it is possible to subject to local etching a material for which the local etching has been impossible to provide since a single etching gas causes a reaction too fierce or causes almost nearly no reaction.