Abstract: A method for manufacturing a multi-layer circuit board including an extreme fine via according to an embodiment of the disclosure may include: providing a board having one surface on at least a part of which an upper conductive layer is formed and the other surface on at least a part of which a lower conductive layer is formed; forming a lower metal layer on the other surface of the board; forming a first resist layer on the one surface of the board through a photolithography process, and forming a first opening on the first resist layer; forming a metal pillar by plating the first opening by using an electrolytic plating method; removing the first resist layer; forming an insulating layer on a location from which the first resist layer is removed; and evenly polishing the metal pillar and the insulating layer.