A method of forming an antireflection optical body (16a) includes: an application step of applying an adhesive (12) other than an epoxy adhesive onto an adherend (11); a fixing step of pressing a substrate film (15) having a fine structure body (16) at one surface side thereof against the adherend (11) from an opposite surface side to the one surface side to fix the adherend (11) and the fine structure body (16) through the adhesive (12); and a peeling separation step of releasing the pressing of the substrate film (15) and peeling fixed fine structure body (16) that is fixed to the adherend (11) through the adhesive (12) from the substrate film (15) while separating the fixed fine structure body (16) from fine structure body (16) on the substrate film (15) at a location where the fine structure body (16) is fixed to the adherend (11) such that the fixed fine structure body (16) is formed on the adherend (11) as an antireflection optical body (16a).