Functional layer removal method and functional layer removal device

Provided is a functional layer removal method which efficiently removes a functional layer from a laminate film, which has a functional layer, without requiring high-alkalinity conditions or high-temperature/high-pressure conditions. Also provided is a functional layer removal device capable of being used in such a method. A functional layer removal method according to an embodiment of the present invention removes a functional layer from a laminate film including a substrate layer and the functional layer. (i) An aqueous solution including a surfactant and a tool which applies ultrasonic waves and shear force are brought into contact with the functional layer. (ii) The laminate film is introduced into the aqueous solution containing the surfactant and stirred, the mass ratio of the laminate film and the aqueous solution being 1:2.5 to 1:4. (iii) The aqueous solution containing the surfactant is brought into contact with the functional layer, the aqueous solution being at least one solution selected from solu