We have demonstrated the formation of microdots on the surface of densified silica glass by thermal relaxation. Silica glass was densified by approximately 4% with a hot isostatic pressing technique. A small area on the glass surface was heated to sufficiently high temperatures under an ambient pressure to induce structural relaxation by repeated irradiation of focused beam pulses from a CO2 laser. A bump with a Gaussian shape was formed in the small area on the glass Surface after the irradiation. The distribution of temperature on the irradiated surface due to the laser beam profile, optical absorption and thermal diffusion was inferred as the origin of the bump shape. This process provides us a new method of producing components for microoptics consisting of only silica glass. [DOI: 10.1143/JJAP.42.L712].