A processing method for glass substrate of the present invention includes: applying heat and external force to a glass substrate and then cooling it down to thereby form a compression stressed part having a different etching rate from that of other parts with respect to an etching reagent to be used, on the surface of the glass substrate and in the vicinity thereof, and performing chemical etching using the etching reagent on the glass substrate having the compression stressed part formed thereon, so as to form a relief on the surface of the glass substrate.