An etching method of subjecting a base material to an etching process using an etching agent containing hydrogen fluoride and ozone is disclosed. The base material has a first region constituted from silicon as a main material and a second region constituted from SiO2 as a main material. The etching method includes the steps of: preparing the base material; and supplying the etching agent onto the base material to form a step between the first and second regions using a feature that an etching rate of silicon by the etching agent is higher than an etching rate of SiO2 by the etching agent, so that the height of the surface of the first region is lower than the height of the surface of the second region.