A technique regarding film formation capable of forming a three-dimensional pattern successfully is provided. A film forming method for a processing target object is provided. The processing target object has a supporting base body and a processing target layer. The processing target layer is provided on a main surface of the supporting base body and includes protrusion regions. Each protrusion region is extended upwards from the main surface, and an end surface of each protrusion region is exposed when viewed from above the main surface. The film forming method includes a first process of forming a film on the end surface of each protrusion region; and a second process of selectively exposing one or more end surfaces by anisotropically etching the film formed through the first process.