Abstract: A process is provided for working a base material which essentially consists of a ceramic material. The process includes an irradiation process of irradiating a laser beam or an electron beam to the base material in order to form an affected portion having cracks in the base material and a removing process for removing the affected portion. The ceramic material includes an oxide ceramic material (for example, alumina and forsterite) and a carbide ceramic material. The shape and the depth of the portion to be worked are controlled by the scanning of the laser beam or the electron beam. The removing process can include any one of the processes of vibrating the base material, applying a thermal shock to the base material and etching the base material. In accordance with the present invention, a base material which essentially consists of an oxide ceramic material or a carbide ceramic material can be worked with high aspect ratio and in a shorter period of time than in a conventional process.